Check the oil level in the automatic transmission. Where is the dipstick located on the gearbox

All owners of cars with automatic transmission need to monitor not only the condition of the oil in the box, but also its level.

The procedure for checking the amount of gear oil is significantly different from the same mechanics, and has its own characteristics.

Consider why checking the oil level in an automatic transmission, or rather ATF fluid, is so important and why its amount can change. By what symptoms can you understand that the level is above or below the norm, what consequences this can lead to, and how to make measurements correctly.

A lack of fluid in an automatic transmission may occur after prolonged use, due to leakage and evaporation of ATF. If the leak occurs quickly enough, such as when a pan is punctured, the car will refuse to drive almost immediately. Much more dangerous is a small flaw, it will kill the box slowly and unnoticed by the owner.

Symptoms

• Slippage and downshifting when driving, especially on a climb, when the pump begins to take air from the sump instead of oil.
• Jerks when shifting gears.
• The howl of the box and the change in the sound of work at different speeds.

Consequences

A low oil level violates the temperature regime of its operation - a smaller amount heats up much faster, the liquid begins to “burn out”.

The pump will entrain air along with the oil, resulting in an air-oil emulsion, which is a compressible liquid. The torque converter in the automatic transmission works precisely due to the pressure of the liquid, and a change in its characteristics will affect the correct operation of this unit, and the entire box as a whole.

There will be a decrease in the ATF resource, it will have to be changed much faster.

The lubrication of the box parts and heat sink will deteriorate, as a result - a decrease in the resource of the automatic transmission itself.

High ATF

The main reason for the high oil level is just incorrect measurements, after which the car owner begins to add liquid to the box on his own.

When replacing at a service station, workers can also fill in too much. The reason is simple: hot fluid is drained, cold fluid is poured in, and hot ATF has a much larger volume. This means that the cold one will subsequently expand even more.

Symptoms

You can determine that the oil level is above normal by the following signs.

• The box starts to blunt, kick, gears may not turn on.
• ATF leaks around the breather, dipstick, oil seals. It is no coincidence that it has a red color, which distinguishes it from all other process fluids.
• Foam on the dipstick. At what not just the presence of bubbles, but a stable foamy liquid.

Consequences

The friction discs begin to slip relative to each other, and this leads to their combustion and increased wear.

The consequences of overfilling are almost the same as with underfilling. The liquid begins to reach the rotating parts of the box and foam, forming an emulsion. But besides compressibility and poor heat transfer, you also get a serious increase in the volume of ATF, the excess of which will be ejected through the breather of the automatic transmission ventilation system.

How to check the oil level correctly

Probe box

It is precisely because of the great importance of the amount of ATF in the machine that it is important to be able to measure it correctly.

If the technical documentation for the car does not contain clear instructions on the method of verification, use the generally accepted rules for all automatic transmissions.

1. The measurement is made on the transmission warmed up to operating temperature. It is important to warm up the box and the liquid in it, and not the engine. It is difficult to do this at idle, you need to drive at least 10-15 kilometers.
2. Measurements are made with the engine running. Only in this case, the liquid circulates throughout the system, and does not stand idle in the crankcase.
3. The selector lever is in position P (Park). In this position, the radiator valve opens and fluid circulation is carried out in full.

After you have warmed up the car, it must be installed on a flat, horizontal surface, the automatic transmission must be switched to P mode. Remove the dipstick and wipe it dry, reinsert it all the way and remove it to check the oil level.

You can download a list of manufacturers and cars with automatic transmission and determine which gearbox you have.

Most often on the probe you can see the inscriptions COLD (cold) and HOT (hot), some immediately indicate the temperature. They also have notches or risks, indicating the permissible range of the oil level. There are always several values, and the reason is that the ATF fluid has a fairly high level of thermal expansion. This means that the volume of oil in an automatic transmission is highly dependent on its temperature.

If, when checking the oil level, the ambient temperature differs from +20 (sometimes the temperature is indicated on the dipstick), the COLD value readings may be incorrect. Many owners of automatic transmissions complain that the fluid level does not even reach the minimum COLD mark on the dipstick. This is quite possible if the check is performed on a cold, at zero, or negative ambient temperature.

If measurements show that there is not enough fluid, add a small amount and recheck the oil level in the box.

If the indicators exceed the permissible values, remove excess ATF through the filler neck. The easiest way to do this is with a homemade device. It is necessary to put a piece of tube from the dropper on the syringe and pump out the excess. After that, also perform a control check.

Probeless automatic transmissions

And how to check the oil level in an automatic transmission if there is no dipstick on it? For example, boxes DP0 / AL4, for Peugeot, Renault, Citroen with engines up to 2 liters. Each of them must have a control plug, it can be located anywhere: on the pallet, in the housing, in the crankcase wall. In some cars, it is also a filler (ZF boxes on BMW), oil is poured into them until it starts to flow back.

“Can I check the oil level in the automatic gearbox myself?” - this question often arises among motorists. At first glance, the procedure is quite simple, but there are nuances, not taking into account which you can get a large measurement error.

Checking the lubricant level

Timely checking the level of lubricant in an automatic transmission affects the protection of the internal mechanisms of the unit from wear. If you take measurements using the wrong method, you will get wrong results. Before starting work, read the vehicle maintenance manual. It indicates the presence or absence of a dipstick for measurements, as well as the sequence for correctly checking the fluid level in the automatic transmission.

When heated, the transmission mixture expands. Pay attention to the oil temperature at which measurements are taken, most manufacturers recommend warming up the car for 20 minutes before starting measurements so that the lubricant is heated to a temperature of 60 0 C. There are factories that indicate that measurements are taken when the mixture is heated to 90 0 C. Factory recommendations - the manufacturer cannot be ignored, because for different types of automatic transmissions a lubricant with a certain viscosity is used, corresponding to the design features of the unit, obviously: the heating rate of different types of oils is different.

Experienced drivers know one more nuance: the presence of a large number of cavities in automatic boxes, inside which lubricant can accumulate, leads to a large error in the measurements obtained, so in order to get the correct measurements, you need to check the oil level for several days at intervals of 1-2 days, then calculate the average arithmetic. Control measurements allow you to more accurately check the gearbox fluid level.

Before checking the automatic transmission oil level, it is necessary to determine the type of box. To do this, look under the hood of the car or look in the instructions for the car. The probe, as a rule, ends with a bright pen. If there is only one handle under the hood, there is no second dipstick, you can measure the lubricant level in the gearbox by unscrewing the control plug of the box.

Watch a video on how to check the level of lubricant in an automatic transmission:

Probe method

You can correctly perform measurements by adhering to the following algorithm:

1. It is allowed to measure the level of lubricant at normal operating oil temperature (60-90 0 C, 13-25 kilometers of car run). Do not perform this procedure on a cold engine. Please note that the automatic transmission only warms up during the trip.
2. Place the machine on a horizontal, level surface. Put the selector in position "Parking". Let the drive run for another 3 minutes.
3. Remove the control probe, wipe it dry with a rag.
4. Return the dipstick to its original place, then remove it again.
5. The level of the lubricant mixture is the extreme dry place on the dipstick. Many automatic boxes have marks on the dipstick with the designations "Hot" - for a warmed-up unit and "Cold" - respectively, for measurements on a cold drive. Using the marks with the designation "Cold", determine the amount of oil in the box, do not confuse it with the level of lubricant. Look at figure 1.
6. The mixture level must be between the minimum and maximum marks of the zone marked "Hot".

Figure 1. Marking on the probe.

When checking, look for the presence of small particles of metal or dirt in the transmission fluid; these impurities indicate wear on the mechanisms inside the box. Changing the color of the oil to black indicates overheating of the fluid, it needs to be replaced. To obtain reliable measurement results, repeat checking the oil level in the automatic transmission several times, if the fluid is always between the maximum and minimum marks, there is no need to add lubricant.

Method without probe

If there is no gearbox dipstick, it is impossible to check the fluid level inside the box, it can only be set.

Automatic boxes of this type have an overflow system consisting of the following elements:

• control plug;
• drain tube.

Figure 2. Drain tube and control plug.

Look at figure 2, it shows:

1. Fill hole;
2. Automatic transmission housing;
3. Control plug;
4. Drainage tube.

Figure 3. The design of the automatic box without a probe.

The height of the drain tube (pos.4) determines the rate of oil poured into the box. If you unscrew the control plug (pos.3), then excess oil will begin to flow, which is above the level of the upper hole of the drain tube. This system allows you to protect the box from overflowing lubricant, but it is quite inconvenient for maintenance.

To check the level of the transmission mixture in an automatic transmission of this type, use the algorithm:

1. Warm up the liquid in the box for this, drive a car 13-25 kilometers.
2. Drive the car into a pit or overpass, the car must be in a horizontal position.
3. Set the selector to the "Parking" mode.
4. Slowly unscrew the control plug. A little mixture will flow out of it, which got into the drainage tube during the operation of the gearbox. See figure 3 for the location of the control plug or refer to the instructions for the machine.
5. Top up to a normal level - about 200 gr. oil through the filler neck of the box.
6. Add lubricant until fluid drips from the drain hole.

Check the drained oil for contamination, make sure the fluid does not smell burnt, otherwise change the lubricant. Take measurements in time, adhering to the interval specified by the manufacturer. Timely execution of the above measurements affects the resource of the unit.

What is the interval from oil change to automatic transmission oil change? When to change the oil in the gearbox?

The correct operation of the gearbox depends on the oil level in the automatic transmission. The condition of the oil plays an important role. In order to avoid any problems, an oil check should be done at least once every 2-3 weeks.

The content of the article:

Depending on the brand, model and equipment of the car, the parameters of operation and measurement of its parameters may differ. As an example, this is an oil measurement in manual transmission and automatic transmission. In this article, we will consider measuring the oil in an automatic transmission, since this type of box is much more finicky compared to mechanics.

Often, drivers do not even suspect that when driving a car with automatic transmission, it is worth looking at the oil level from time to time, especially warming up the box in the cold season.

The concept and principle of operation of automatic transmission

allows you to drive a car, the transmission of which is changed without driver intervention. The main parts of the automatic transmission are: a torque converter, the main task of which is to transmit torque, clutches, spools, gearboxes and shafts.

In addition, there are 2 types of automatic transmission operation. The first is called hydraulic, which is based on oil pressure on the pedals. The second type is electronic control. The principle of operation is that solenoid coils occupy an important place here and control depends on their movement.

Wrong level

It must be remembered that too high or too low an oil level in the automatic transmission can damage the technical condition of the gearbox. If the level exceeds the maximum mark at fairly high speeds, it begins to foam and, as a result, overflow.

Thus, it threatens to leak oil, which leads to insufficient oil levels. Also, car parts become unusable faster. In turn, a low level leads to the fact that air enters the gearbox and, as a result, the normal temperature regime is disturbed. This mixture degrades the quality and performance of the gearbox. In this case, the box can quickly overheat, and the parts wear out very quickly.

The level must be checked regularly, as this will prevent possible breakdowns or oil leakage. Also, the condition of the fluid will tell you about the need to replace it and parts.

Oil level check procedure

There are two ways to check the oil level. This procedure in itself is not complicated, however, it requires certain knowledge and care.

The first method involves the use of a special dipstick to measure the oil level. First you need to drive the car on a flat road. Next, turn on the "Parking" mode so that the car does not budge. Then, you need to open the hood and inspect the details. Near the gearbox there should be a special probe on which ATF is written. Another important condition for checking is the fact that you need to check the level when the engine is warm.

There are different types of probes, but the principle of their work is the same. They have special marks showing the maximum and minimum values ​​​​separately for cold and hot liquids or for both equally.

Before starting the procedure, wipe the probe with a rag so that dirt does not get inside. Then lower the dipstick for a few seconds and pull it out. The level must not exceed the maximum mark or be below the minimum. If the level is unsatisfactory, then you need to add oil.

For more accurate results, the procedure should be repeated several times. Also, when checking the level, you can pay attention to the oil itself. If its color has darkened, this may indicate that the oil has overheated and should be replaced.

The second method is provided for those cars that do not have a dipstick. In this case, it will be more difficult to check the level and it will take more time. First of all, you need to be very careful as there is a risk of oil leakage. The car needs to be slightly raised with a jack. The engine, as in the first case, should be well warmed up.

The design of the automatic transmission provides for the presence of special pipes designed to drain and prevent oil leakage. Before starting the test, carefully uncork the cork. In this case, a certain amount of oil will pour out. Therefore, under the cork, you should put a container into which it will merge.

It will also make it clear about the condition of the fluid and the need to replace it. The next step is to add fluid to the tank until it starts to slowly pour out. Only then will the level reach the norm. Excess fluid will flow out on its own and the oil will reach its optimum level.

The cost of checking in a car service

Safely and quickly checking the oil in the automatic transmission can be carried out by the masters in the car service, in the case when you do not understand the correctness of the measurements at all. You should refer to such a procedure at least once a year, but if at a car service, you can do it again. The price for this service is $20. If the automatic transmission fails, then its repair or replacement will cost more than $ 1,000.

Video of oil check in automatic transmission:

The automatic gearbox is a design that for several decades could only be found on expensive foreign-made cars. Today, automatic transmission is far from an exclusive phenomenon; many cars, both domestic and foreign, are equipped with such a system that greatly simplifies the life of a car owner in terms of driving. When driving a car, you can forget about the clutch pedal, which must be regularly squeezed out when shifting gears in mechanical systems.

Regulations for the correct check of the oil level in the automatic transmission.

An automated gear shift system is a complex mechanism that requires constant proper care, since its failure can threaten significant financial costs. And the main direction of concern for the automatic transmission is the regular monitoring of the oil in the system, its replacement as soon as necessary. In this article, we will figure out how to check the level, how much of it is considered the norm, and what threatens its reduced or increased amount.

How to check the oil level in the automatic transmission?

The presence and compliance with the norm of the lubricating fluid guarantees controllability and reliability in the operation of the vehicle due to the correct functioning of the transmission units. Malfunctions in the operation of automatic transmissions are exactly the case that is better to prevent than to eliminate the consequences later. An automatic system is quite expensive, and its repair also does not fall into the category of penny costs.

An effective measure to prevent automatic transmission malfunctions is considered to be a periodic check of the indicators and condition of the oil, as well as a replacement if the lubricant has already worked out its own. The procedure for monitoring the criteria of a lubricating fluid is not particularly complicated and does not take much time, therefore, any person, having familiarized himself with the methodology for its implementation, will be able to prevent serious machine breakdowns by spending a few minutes every few weeks.

To look for the correct answer to the question of how to properly check the oil level in an automatic transmission, the most competent way is in the user manual for the vehicle, where the manufacturer describes this procedure step by step. If for some reason you cannot use the instructions, then we will describe in detail how to check the oil level in an automatic transmission of various modifications.

Box modified with dipstick

The vast majority of modern vehicles are equipped with automatic transmissions with a special dipstick, which is provided by the automaker for routine checks of oil in the transmission by the owner of the car. The first task for the car owner is to find out where the oil level dipstick is located in the automatic transmission, and whether it is in this car model. You can find out where the oil level dipstick is located from the user manual or by independently studying the engine compartment. Most often, the device is located near the rear of the motor, closer to the bulkhead of the engine compartment. In order to see it, you need to open the hood and stand in front of the car, across its movement. The desired part is located on the right hand, it looks like a handle painted in a colorful color, on the left hand there is also a dipstick - this is a device for controlling the oil in the power unit.

In some models of machines, there are two dipsticks nearby: to check the level of lubrication in the engine and in the gearbox, then you will have to navigate by the color of the fixture handle. As a rule, the dipstick for checking the lubrication in the motor is yellow, and the other handle will be painted in a different bright shade - this is the dipstick for monitoring the oil level in the automatic transmission.

After the toolkit is found, you can begin to check the criteria for the lubricating fluid. If the car owner pulls out the dipstick for visual inspection, he will see that the device has two engravings - COLD and HOT - with two marks next to each of the values. The specific marking of the probe is very different from its standard appearance in mechanical boxes. The fact is that this procedure can be performed in two ways: the first is control on an unheated automatic transmission, which gives an estimated result, the second is accurate monitoring of the fluid level on a heated box to functioning degrees. Consider what the oil level in the automatic transmission should be on the dipstick when checking it in different ways.

For diagnosis, regardless of the method, it is important to install the car on an extremely flat horizontal surface.

Level control on a cold automatic transmission is carried out in the following way:

The results of checking the oil criteria on a hot automatic transmission are considered more reliable. Before performing the procedure, you need to warm up the car to operating temperatures by driving about fifteen kilometers on it. Drive the box through all positions, with the engine running, check the level according to paragraph 2 above the instructions provided.

Assess the oil level by comparing its criteria with the HOT value on the dipstick. The norm is the position of the oil level between the marks near the inscription HOT. With an increased or decreased level of lubricant, it must be removed or topped up to the level, respectively. This method of verification gives more reliable and error-free data if the procedure is carried out correctly. Professionals advise checking the level only after the gear oil has warmed up to operating temperatures in order to get the most accurate results.

Box without dipstick

The methodology for diagnosing the level of lubrication using a dipstick is not particularly difficult and can be performed by any car owner on their own. And how to check the oil level if the vehicle is not equipped with a dipstick from the factory? In vehicles equipped with automatic transmissions without a probe, most often the emulsion is not supposed to be replaced throughout the entire operating period of the car, or the automaker is trying in this way to deal with unauthorized interventions in the transmission system, providing for its maintenance exclusively in.

Automatic transmissions without a dipstick have only two openings - an oil drain and an oil filling opening. In these boxes, excess lubrication is impossible, since the system is equipped with a special tube through which excess fluid is removed into the sump during the operation of the machine. However, it is much more difficult to determine the decrease in oil indicators in such automatic transmission modifications, to find out its level than in the previous case, because if you are not one hundred percent confident in your abilities, then it is better to abandon this idea, use the services of professionals.

Consider step by step how the current craftsmen check the oil level in the automatic transmission at home:

When checking the lubricant level in parallel, it is important to evaluate its appearance for impurities and slag components, which are an indicator for. Having figured out how to check the oil level in the automatic transmission and having carried out this procedure on your own at least once, the car owner will forever save himself from the need to regularly visit the service station for this purpose, significantly saving his budget. Let's take a closer look at how underfilling and fluid overflows are dangerous for the gearbox, what will happen if the problem is not detected in time, or simply ignored such precedents.

The consequences of operating the machine with a reduced fluid level in the automatic gearbox

For novice car owners, the only way to detect a low oil level is to check its criteria using the above regulations. However, experienced drivers can even determine a low automatic transmission oil level by the behavior and reaction of the car on the road, based on the following symptoms:

• deterioration of vehicle controllability;
• appearance from the transmission nodes;
• reduced response of the machine to gear changes.

These circumstances inform the driver that the automatic transmission has a low oil level, respectively, it needs to be topped up to the norm or the lubricant needs to be replaced if the machine has been operated for a long period in the oil starvation mode of the transmission units.

Why are situations so dangerous when the emulsion level in the box is below normal? The fact is that in the system the circulation of fluid is ensured by pumping it with the help of an oil pump. If there is a shortage of fluid in the system, the pump begins to capture air along with the lubricant, driving it through the system. The consequence of such a precedent is the compression of oil under air pressure, which results in poor-quality lubrication of contacting parts and the appearance of a huge number of metal chips in the liquid, which special magnetic elements do not have time to screen out. Contaminated oil, circulating through the system, does not cope with its tasks, which leads to deformation and wear of the working working units.

High oil level in automatic transmission: how dangerous is it?

The situation with excess oil in the automatic gearbox is possible only in cars that are modified with a dipstick. In boxes not equipped with a dipstick, excess oil is automatically discharged through a special tube, which eliminates the possibility of such precedents. An increased level of lubrication is considered, which, when checked, is noted above the maximum mark on the dipstick. An abundance of lubricant in an automatic transmission is no less dangerous for the box than its deficiency. With an excess of liquid, its strong foaming occurs, the oil begins to quickly oxidize and evaporate against the background of high operating temperatures, which is fraught with failure of the valves and friction parts of the system.

When operating the machine in the mode, the consequence will be a change in the composition of the oil at the molecular level, a decrease in its quality characteristics, which will affect the efficiency of its operation and result in expensive repairs for the car owner. To avoid such consequences, it is important to regularly check the level of lubrication according to the regulations, and when replacing at home, clearly follow the recommendations of the automaker for the optimal fluid volume.

The optimal oil level in the machine is its criteria on the dipstick approximately in the middle between the minimum and maximum marks, and the marks on the dipstick are the extreme allowable liquid limits. Experienced car owners and professionals advise diagnosing oil readings in automatic transmissions according to the following recommendations:

• carry out checks in accordance with the regulations from the manufacturer;
• do not ignore even minimal deviations from the norm of the lubricating fluid;
• when checking the level, evaluate not only the fullness of the system, but also visually analyze the state of the liquid for impurities and coarse particles, and perform scheduled oil changes in accordance with the regulations.

Summing up

Monitoring the oil indicators in an automatic transmission is the direct responsibility of every car owner, since the reliability, controllability and safety of the car on the road depend on the quality of the automatic transmission. You can carry out the task both on your own and using the services of service center employees, which will be cheaper than repairing the box or replacing it.

This article provides instructions for carrying out these operations on various modifications of automatic transmissions installed on cars, according to which even an inexperienced car owner can learn to control the level of lubrication in the automatic transmission of his car on his own. This will help not to miss the moment when the oil criteria deviate from the level, and take preventive troubleshooting steps in time.

How to check the oil level in an automatic transmission? For most vehicles, the oil level (ATF) in the automatic transmission (AT) is checked with the engine running and the Range Select Lever (RVD) in the "P" position. On the dipstick for measuring oil in automatic transmissions, as a rule, there are several marks. The top two, and sometimes the only ones, correspond to the normal level of oil heated to operating temperature (90 ° C).

Often this area of ​​the probe is marked with a notch and / or the inscription "Hot". In order for the oil in the automatic transmission to warm up to operating temperature, it is necessary to drive 15-20 kilometers. After warming up the oil in the automatic transmission, install the car on a flat, horizontal platform. Pull the dipstick out of the transmission and wipe it dry. Then insert the probe back into the probe tube until it stops and remove it again. The lowest, dry place on the dipstick will correspond to the oil level in the automatic transmission. Sometimes there are also lower marks on the dipstick corresponding to the level of cold. This mark is intended for an approximate determination of the amount of oil filled in the event of an oil change.

Finally, the level, anyway, should be checked after warming up the oil. Often it is written on the dipstick in which position the high pressure hose should be checked for the level and type of oil used. There is a special case - Honda and Acura cars. They also check the oil level after reaching the operating temperature of the oil, but with the engine turned off. There are automatic transmissions in which the oil level is checked when the high pressure hose is set to the "N" position. Such transmissions are used on Mitsubishi, Proton and Hyundai front-wheel drive vehicles. Note that we are not talking about car models, but about transmission models.

So, for example, front-wheel drive boxes and Mitsubishi can be found on Chrysler cars and vice versa. If you have a Proton or Hyundai car, then the oil level in the automatic transmission should be checked in the "N" position of the high pressure hose. In the case of a Mitsubishi or Chrysler transverse engine, look at the automatic transmission from the wheel side. If there is a stamped side cover secured with ten bolts, then you have a Chrysler automatic transmission, and the oil level should be checked when the high pressure hose is in the "P" position. The absence of such a cover indicates that your car is equipped with a Mitsubishi automatic transmission, and the oil level should be checked when the high pressure hose is set to the "N" position. Also, in the "N" position of the RVD, the level is checked on Jeep Cherokee and Jeep Grand Cherokee cars with automatic transmission manufactured by Chrysler. But on some models of these cars, Aisin Warner automatic transmissions are installed, in which the oil level should be checked in the “P” position of the high pressure hose. To determine the type of box installed on your car, you can use the following method. The Aisin Warner automatic transmission has a rectangular sump, the dipstick pipe is welded directly to the sump on the side, and there is a drain plug at the back of the sump.

For Chrysler automatic transmissions, the pan is almost square, the dipstick pipe is installed in the gearbox crankcase and there is no drain plug. In addition, checking the oil level in the automatic transmission of VW, Audi cars with three-speed gearboxes should be carried out when the high pressure hose is set to the "N" position. In some automatic transmissions, instead of a dipstick, there is a control plug in the crankcase. The disadvantage of this is that to check the oil, you need to put the car in a "pit" or raise it on a lift. But there is an advantage: you will never pour oil into the automatic transmission, which is very important. Such plugs have ZF automatic transmissions, which, as a rule, are equipped with BMW cars. Moreover, on BMWs with five-speed gearboxes, the same plug also serves to fill the oil. For safety reasons, the level control in this case is carried out with slightly warm oil. This is European fashion. On the "Americans" we met such a level check procedure only in the 4T40E automatic transmission. It should be noted that there is an automatic transmission, which, in general, does not provide any devices for determining the oil level. This is the Mercedes 722.6 transmission, which is now installed on almost all cars of this company. The fact is that the container where automatic transmission oil is poured is connected to the oil pan through a bypass valve, the purpose of which is to maintain the required oil level in the pan. Therefore, the level of the filled oil is not as important as for other transmissions.

What are the dangers of low or high oil levels in automatic transmissions?

Too low an ATF level is dangerous because the pump, along with the oil, begins to capture air. The result is an air-oil "emulsion" that is highly compressible and has low heat capacity and thermal conductivity. The oil loses its most important properties and becomes compressible. The consequence of this will be a decrease in pressure in the control system, poor heat removal from the automatic transmission, deterioration in the lubrication of rubbing elements. Operating a car with foamed oil in an automatic transmission will quickly disable the box. I would like to note that you should not confuse individual large air bubbles in the oil on the dipstick (which sometimes happens) with foaming oil, which is a uniformly foamed liquid with very small air bubbles. Foaming the oil increases its volume, so when checking the level, it will be too high.

In this case, turn off the engine and let the oil settle for some time, and then, without starting the engine, check the oil level. If the probe turns out to be completely dry, then you can safely add a liter, or even two. The oil can also foam up the rotating parts of the automatic transmission if the level exceeds the allowable value. In this case, the rotating parts of the automatic transmission begin to dip into the oil and foam it. Foaming does not occur immediately after starting the engine, as is the case with a low level, but during movement, especially with high engine speeds. Both in the case of an underestimated oil level, and in the case of an overestimated level, foaming of the oil leads to an increase in its volume, and, as a result, to its emission through the gearbox breather. Looking under the car, you can often see there that the whole box is in oil.

Here is a case from practice. Ford Explorer came for diagnostics with a complaint that something incomprehensible was happening with the level. The level - that is, it is not, and the automatic transmission is all in oil. In a conversation with the client, it turned out that the dipstick was lost and replaced with a new one ordered by VIN from the dealer. When comparing the stylus and the stylus tube, it turned out that the stylus is much shorter than the tube. The ATF level was just at the level of the box axis. (Usually the level is approximately flush with the pan gasket.) Thus, the customer's complaint was caused by too high ATF levels in the automatic transmission.

The level is normal, but the ATF is foaming, what is the reason?

This is possible in case of damage to the filter seal or the filter itself.

The level is constantly decreasing, and there are no signs of oil leakage.

The prerequisite for such a malfunction is the presence of a vacuum modulator in some types of automatic transmissions - a special device that generates pressure proportional to the degree of vacuum in the engine intake manifold. Outwardly, the vacuum modulator resembles a similar device on a Zhiguli distributor. The modulator is connected to the intake manifold by a tube through which, in the event of a malfunction of the modulator membrane, oil from the automatic transmission enters the manifold and burns out. Typical representatives of cars equipped with an automatic transmission with a modulator: Ford Scorpio, Ford Sierra, Ford Explorer, Mercedes, front-wheel drive cars of the General Motors concern with four-speed automatic transmissions. It should be noted that since the beginning of the 90s, the use of modulators has been abandoned and replaced by electrical sensors.

Another reason for lowering the level of ATF in the automatic transmission in the absence of a leak may be a violation of the tightness of the cooling system. Many vehicles have an automatic transmission oil cooler built into the engine antifreeze cooler. If the built-in radiator is leaking, oil enters the engine cooling system, as a result of which the antifreeze turns into a pinkish emulsion.

How much oil should be poured into an automatic transmission?

Depending on the type, the automatic transmission can hold from 4.2 liters (DAIHATSU TERIOS) to 15.5 liters of ATF (FORD EXPEDITION). It must be borne in mind that when replacing, not the entire volume of oil is drained. Part of the oil remains in the channels of the control system, and, in addition, not all transformers have plugs for draining oil from them. Therefore, when draining the oil, part of it remains in the automatic transmission, but this is considered acceptable. If you want to completely change the oil, two or three oil changes are necessary.

How to determine what is filled in the automatic transmission, and what kind of oil to fill in when replacing it?

Gear oils differ in both color and smell. There are light yellow oils, and there are red shades (from light CASTROL to rich red ELF). It should be said right away that the color of the oil is determined only by the dye that is added to it so that automatic transmission oil can be distinguished from other oils used in the car. Nothing else determines the color of the oil.

In addition, after a short period of time, any oil acquires a transparent brown color. Given that when changing the oil, not all of its volume is updated, and also that the color and smell of the oil change during operation, it is practically impossible to determine its brand, even if it has changed recently. At least one, and preferably two-time oil change is necessary (in the absence of serious problems in the operation of the automatic transmission). You should use the oil that is specified in the operating instructions for the car. It happens that the type of recommended oil is also indicated on the dipstick. In addition, oil manufacturers produce posters and albums (they can be found in specialized stores) with a list of car brands and recommended oils, both motor and transmission.

Usually, the instruction manual recommends using a well-defined type of oil. Probably, there is not only a technical, but also a commercial justification for this. For example, Chrysler and front-wheel drive Mitsubishi (Hyundai) use Mopar ATF 7176, and the instructions indicate that this oil has increased frictional properties compared to Dexron or Mercon. But on the dipstick of the Dodge RAM and Jeep Grand Chrokee, you can find recommendations to fill in Mopar ATF 7176 or Dexron II. So it's still possible.

Another example: Mobil does not recommend mixing different types of oils, even its own production. And here is a quote from a bottle of Mobil Synthetic ATF: "Compatible with conventional ATF fluids" (Compatible with conventional automatic transmission oils). When it comes to changing the oil in the engine, the algorithm is simple. We go to a reputable store, choose an oil manufacturer (according to one criterion we know). From the entire range, we choose oil for gasoline or diesel engines, select the oil class according to API (so that it is not lower than in the operating instructions) and the desired viscosity according to SAE. All.

Why, when it comes to transmission, do we start looking for green oil without sparing time and money? Is it because the automatic transmission is a more exotic unit than the engine? The experience of repairing several thousand automatic transmissions suggests that the causes of breakdowns are more prosaic than mixing different types of oils when changing it. Transmission operating conditions are of paramount importance, and even the most expensive synthetics will not help if they are violated.

How often should automatic transmission oil be changed?

The oil change period depends on the type of automatic transmission, and, usually, under normal operating conditions, it is recommended to change it after 70 thousand kilometers of the car (or after 2 years), and after 25 thousand kilometers (or after 1 year) if the operating conditions are different from normal (hot climate, cold climate, operation in a metropolitan area, constant operation of the machine with a full load, etc.). For some expensive models (for example, the BMW 750), according to the instructions, an oil change is not provided at all. But no matter what, regularly (once a week) check the quality of the oil in the automatic transmission of your car.

You should adhere to the established replacement periods if during operation there is no significant change in the quality of the oil or you do not get into difficult driving conditions (get stuck, tow another car for a long time, etc.).

If the oil darkens and or acquires a burnt smell, it must be replaced without waiting for the scheduled replacement period. But not always replacing burnt oil can save the day. Most often, in these cases, an overhaul of the automatic transmission is required. When changing the oil in an automatic transmission, it is also necessary to change the pan gasket and filter.

In some types of automatic transmissions, filter replacement during an oil change is not provided, because. the filter is not accessible without removing and disassembling the automatic transmission (for example, Daewoo Espero, Nissan Maxima (with RE4F02A gearbox), SAAB 900 and 95, Volvo 850, front-wheel drive Opel models with a four-speed automatic transmission).

How to evaluate the quality of oil in automatic transmission?

Different types of oils differ in both color and smell. If your box has recently been repaired, remove the dipstick and note the color and smell of ATF. If during operation the color or smell has changed a lot, then there is a reason to contact the service to check the condition of the automatic transmission.

When buying a car with an "automatic", the oil should be transparent and not have a dark brown tint or a burnt smell. Drip the oil from the dipstick onto a white paper towel and check that the oil is easily absorbed and free from foreign matter. If the oil in a faulty automatic transmission was changed several times in a row before the sale, then after a careful analysis of the oil drop, you can still distinguish small black particles in it that are not in harmony with the transparent and bright oil. Often you can see a black coating on the dipstick. In this case, it is necessary to wipe the dipstick well and re-analyze the condition of the oil. If the raid did not reappear, then it means that the previous one was a consequence of the fact that the probe had not been used for a long time. It also does not hurt to look into the engine cooling system and make sure that the antifreeze is transparent and does not contain a water-oil emulsion. Keep in mind that you can find red antifreeze, which at first glance resembles automatic transmission oil.

What oils are used in automatic transmissions other than automatic transmission oil?

In front-wheel drive automatic transmission designs, as well as in some all-wheel drive transmission layouts (for example, AUDI, SUBARU), the main gear and differential are located in the same crankcase with the gearbox. This arrangement is called transaxle, in contrast to transmission, when the main gear is in the rear axle. If the main pair is in the same housing with the automatic transmission and is a hypoid gear, then oil for hypoid gears is poured into the differential housing (separate lubrication). In other cases, lubrication can be either separate or joint. In the case of a cylindrical, helical gearing in the main gear, as a rule, automatic transmission oil is used to lubricate it. It is not necessary to check the oil level in the differential with joint lubrication. In the case of separate lubrication, as a rule, there is a control plug or dipstick.

How to change the oil in an automatic transmission?

The sequence of actions for changing the oil is the same as for changing the oil in the engine. We drain the old oil, change the filter, fill in new oil. In most cases, the filter pan must be removed to replace the filter. Sometimes the filter is located inside the automatic transmission and is not accessible without dismantling and disassembling the automatic transmission. In this case, the oil change occurs without changing the filter. Along with the filter, the pan gasket also changes. Usually the filter and gasket are sold in one set (Filter kit).

On some models, the pan is placed without a gasket on the sealant. If the filter is made in the form of a fine metal mesh and is not damaged, then you can leave the old one by washing and blowing it with compressed air. Before installing the filter in place, check the quality of the seal of its mounting hole. The filter and pan mounting bolts should be tightened to strictly defined moments specified in the vehicle operating instructions. After you have filled in fresh oil, you must start the engine. Holding the machine with the brake, move the hose to all positions, pausing in each position for a few seconds. Then set it to the "P" or "N" position, check the oil level and bring it to the mark corresponding to the cold state of the oil. Finally check the level only after a run of 15-20 kilometers, when the oil temperature reaches the operating value. In the process of changing the oil, it is necessary to evaluate the presence of wear products located in the sump, on the sump magnets and in the filter.

A small amount of suspension in the oil, non-ferrous metal dust and a slight gray coating on the magnets can be considered the norm. Pieces of plastic, metals, the presence of black scales or clay-like deposits in the sump indicate the need for an overhaul of the automatic transmission, even if there are no complaints about the operation of the transmission yet.

Is the use of ATF additives justified?

Modern oils already have all the necessary additives in their composition. This question is often asked when problems arise in the operation of an automatic transmission. In most cases, problems in the operation of the automatic transmission are accompanied by increased wear of the friction controls. This is an irreversible process and neither oil changes nor additives will restore them. Therefore, by and large, overhaul is the only way to restore the transmission to working capacity.

What do the range selector symbols mean and why are they needed?

The range selection lever (RVD) of the gearbox has several positions, which have an alphanumeric designation. The number of these positions for different car models is different, but on all cars the high pressure hose must have positions marked with the letters "P", "R" and "N". Position "P" Selected when the car is parked for a long time. In this position of the high pressure hose in the automatic transmission, all controls are turned off, and its output shaft is blocked, so the movement of the car is impossible. This mode allows the engine to start. Position "R Reverse. Moving the lever to the "R" position while driving can lead to failure of the gearbox and other transmission elements. In this position, the engine cannot be started. Position "N" In the gearbox, either all controls are turned off, or only one is turned on. The mechanism for blocking the output shaft is turned off, i.e. the car can move freely. In this mode, starting the engine is allowed. For cars equipped with four-speed gearboxes, the RVD of the range has, as a rule, four forward positions: " D", "3", "2" and "1"("L").

It should be noted that if the high pressure hose is installed in one of these positions, the engine cannot be started. Range "D" - the main mode of movement. It provides automatic shifting from first to fourth gear. In normal driving conditions, it is recommended to use it. Range "3" - movement is allowed in the first three gears. It is recommended to use when driving on a hilly road or in conditions of frequent stops. Range "2" - movement is allowed only in first and second gears. Recommended for use on winding mountain roads. Switching to third and fourth gears is prohibited. Range "1" - movement is allowed only in first gear. This range allows maximum implementation of the engine braking mode. It is recommended when driving on steep descents.

On some car models, permission to use the fourth, overdrive, gear is carried out using a special "OD" button. If it is in the recessed position and the RVD is set to position "D", then upshifting is allowed. Otherwise, the inclusion of the fourth overdrive is prohibited. The state of the control system in this case is indicated by the "O/D OFF" indicator. If the use of overdrive is enabled, the indicator is off, and when it is disabled, it lights up.

What are the extra buttons (switches) for? What is winter mode?

On most modern vehicles with automatic transmission, several options for controlling gear changes are incorporated into the control system. These include - economical, sports, winter, etc.

economic program. The program is tuned to ensure movement with minimal fuel consumption. The movement of the car in this case is smooth, calm.

Sport program. This program is set to maximize the use of engine power. The car in this case develops, in comparison with the economical program, much greater accelerations. To implement an economical or sports program, a special button or switch is located on the dashboard or next to the range selection lever, which, depending on the brand of car, may be labeled "POWER", "S", "SPORT", "AUTO", "A / T MODE", etc.

Electronic control units of almost all modern cars have a special program for starting off on a slippery road (winter program). To activate it, there is also a special button or switch, which may be labeled "WINTER", "W", "HOLD", "*", etc. In the case of its action, various automatic transmission operation algorithms are possible, but, as a rule, in all cases, starting is carried out either from the second or from the third gear.

What is overdrive? Which of the modes is preferable in urban conditions drive or overdrive?

Overdrive in the terminology of American automakers means overdrive. Designated, usually, as "OD", either D or D in a circle. Overdrive is recommended for measured, economical driving on the highway.

Can the range selector be shifted on the fly?

It is possible, but not in all positions. It is strictly forbidden to move the high pressure hose to the "P" and "R" positions when moving forward. The lever can only be moved to both of these positions when the vehicle is at a complete stop. Violation of this rule can lead to serious damage to the automatic transmission. In addition, it is not recommended to move the high pressure hose to the "N" position while driving, since in this case the connection between the wheels and the engine is lost and sudden braking can cause the car to skid. And in all other provisions of the RVD can be easily translated. In some cases, it is even recommended to do it on purpose. So the transfer of the RVD from position "3" to position "2" will increase the efficiency of engine braking, etc.

Should the range selector be moved to "N" when stopped at a traffic light?

It only makes sense during long stops in traffic jams in hot weather, to reduce heat generation and prevent overheating of the gearbox oil. In other cases, this is not even recommended.

Do I need to use the parking brake when parked when the range selector is in the "P" position?

For reliable fixation of the car in the parking lot on relatively flat areas, a working mechanism for blocking the automatic transmission output shaft is quite enough. But if the car is on a slope, then the handbrake is required. Moreover, it is first necessary to tighten the hand brake and only after that set the high pressure hose to the "P" position. In this case, you release the automatic transmission output shaft blocking mechanism from the additional load associated with the tendency of the car to roll down.

How to determine the number of gears in an automatic transmission?

In Japanese cars, a four-speed automatic transmission can be identified by an additional button on the high pressure hose, which is labeled "OD OFF" or "Hold". If there is no such button, then most likely the automatic transmission is three-speed without overdrive. In European vehicles, the range select lever for three-speed automatic transmissions is marked with the symbols PRND21. Four-speed - PRND3. Five-speed - PRND4 ...

In American cars, the presence of a fourth (sometimes fifth) overdrive is indicated by a D symbol in a circle. With some experience, you can also determine the number of gears in practice, following the tachometer needle while the car is accelerating. Each shift will be accompanied by some reduction in engine speed. Only in this case, it must be borne in mind that the tachometer needle reacts in the same way to the blocking of the torque converter (however, the drop in speed in this case will not be as noticeable as during gear shifting).

Is it possible to skid on a car with automatic transmission?

Nothing criminal happens during slipping in the automatic transmission. Increased heat generation in the torque converter in this case can be critical if the cooling system has low efficiency (the automatic transmission cooling radiator is clogged with wear products).

How to tow a car with automatic transmission?

There is no single answer to this question either. For some cars there are very strict passport restrictions. For example, the Jeep Grand Cherokee is recommended to be transported only on a tow truck. Chrysler's front-wheel drive is a little easier. Vehicles with a three-speed automatic transmission can be towed at a speed of 40 km/h for a distance of 25 km, and with a four-speed automatic transmission at a speed of 72 km/h for a distance of up to 160 km. And yet, whatever the car may be, in the event of a faulty transmission, a tow truck is preferable.

The fact is that in automatic transmission lubrication is carried out forcibly, i.e. oil is supplied to each friction pair under pressure. If the transmission is faulty, then there is no certainty that lubrication is present. True, indirectly, the performance of the pump can be assessed. It is necessary to compare the oil level with the engine turned off and the engine running. If the level does not change, do not even think about towing. Carry out towing with the engine running and the high pressure hose in the "N" position.

There is another way to tow a car with a failed automatic transmission. Pour as much oil into the automatic transmission as possible, which will provide at least some lubrication of all its parts.

Can a trailer be towed by a vehicle equipped with an automatic transmission?

Allowed. But we must remember that the higher the load, the greater the heat generation in the torque converter. If you regularly use a trailer, consider installing an additional radiator in the automatic transmission cooling system. In addition, in the case of a long trailer towing, the use of overdrive is undesirable. It is better to do this on the "3" or "2" bands.

Do I need to warm up the automatic transmission before driving?

The first time after the start of the movement, it is recommended to avoid dynamic driving until the oil in all units has warmed up to operating temperature. In the cold season, before driving, it does not hurt to warm up the oil in the automatic transmission a little. To do this, it is necessary to move the RVD to all positions, lingering in each of them for a few seconds. Then turn on one of the ranges of movement, and hold the car for several minutes with the brake, while the engine should be idling.

What are the main advantages and disadvantages of automatic transmission?

Automatic transmission enhances driving comfort. The absence of the need to select the desired gear and shift gears allows you to focus on driving, which in a difficult traffic situation will not interfere even with an experienced driver. Due to the presence of a torque converter, the automatic transmission creates more favorable operating conditions for both the engine and the running gear, which increases their resource, and the automatic transmission control system prevents the engine and running gear from overloading due to driver errors. A car with automatic transmission is equipped with a passive safety system that does not allow the engine to be started in positions other than "P" and "N". It also prevents spontaneous movement of the car when parked on uneven ground, tk. The key can only be removed from the ignition switch in the "P" position of the high pressure hose.

The disadvantages of automatic transmissions include lower efficiency (due to losses in the torque converter) than manual transmissions, which increases fuel consumption. Although this is not always the case. Modern automatic transmissions in some driving modes can achieve higher efficiency than manual transmissions by maintaining optimal engine speeds and "intelligent" control of torque converter lockup. Another disadvantage is the slightly worse dynamic acceleration performance of a car with an automatic transmission than with a manual transmission, all other things being equal. The difference is not so great and for the majority of drivers is insignificant. And finally, a car with automatic transmission cannot be started except with the help of a starter. It should be noted that the vast majority of drivers who have experience in operating both types of transmissions, regardless of the level of income and driving experience, give unconditional preference to cars with automatic transmission.

What is a kickdown?

If the throttle pedal is fully depressed while driving, the gearbox will shift down one or two gears. This mode is recommended for obtaining higher acceleration values, which is useful, for example, during overtaking. Reverse upshifting in this case can only occur when the engine reaches maximum speed. If you release the throttle pedal, the transmission will return to normal operation. It should be borne in mind that on a slippery road during a forced downshift, the drive wheels may begin to slip, which can lead to a skid.

What does the automatic transmission cooling system look like?

As already noted, the main source of heat in the automatic transmission is the torque converter. Moreover, at high loads, the heat generation is quite large. The operating temperature of the transmission is comparable to the temperature of the engine, and may exceed it. Therefore, cars with automatic transmission have a special cooling system, the radiator of which is either built into the radiator of the engine cooling system, or installed separately and cooled by air flow. On older cars with a small engine capacity, you can find boxes that have an air cooling system. On the body of the torque converter there are additional external blades, with the help of which they organize the air flow to remove heat.

How to start the movement of a car with automatic transmission?

Before driving, always press the brake pedal, move the high pressure hose to the desired position, without pressing the throttle control pedal. After a light push, you can release the brake pedal and start moving by acting on the throttle pedal to do this.

What are the available methods for checking the condition of the automatic transmission? What is a "Stall Test"?

First, check the level and quality of the oil in the automatic transmission. Secondly, the time for switching on the gear when moving the high pressure hose from "N" to "D" or "R" should not significantly exceed 1 - 1.5 seconds. The inclusion of the transfer can be judged by a characteristic push. Pay attention to the quality of switching during break-in. When shifting gears, there should be no "bumps", vibration and extraneous noise. The moment of gear change should not be accompanied by an increase in engine speed. An experienced driver on the behavior of the car on the road can make a qualified preliminary conclusion about the state of the automatic transmission.

For reference: Tacho-Transmission provides free services - running a car by an experienced driver (test drive), reading fault codes and consultations. Another simple method for checking the condition of an automatic transmission is the Stall-Test. The essence of this test is to determine the engine speed when the car is completely braked and the throttle control pedal is pressed all the way down. By the magnitude of these revolutions, one can judge the serviceability of some elements of the automatic transmission. Immediately make a reservation that the Stall-Test should be performed by an experienced mechanic. Otherwise, you yourself can disable the automatic transmission. In addition, to analyze the performance of an automatic transmission, you need to know the nominal value of the engine speed during the Stall-Test, without knowing which this test will not give you anything.

Is it possible to do without automatic transmission repair if the car sometimes does not drive?

Owners of cars with "electronic" automatic transmissions, in the absence of movement, hope that all the problems lie in failed sensors, after replacing which everything will be fine. There may be problems with sensors, but as they say: "It's too late to drink Borjomi ...". The fact is that control algorithms do not provide for blocking movement in the event of any failures in the system. Even if all the wires and sensors are torn off from a working automatic transmission, the car will not lose the ability to move. There will be no good dynamics and gear changes, but you can go.

The lack of movement forward or backward, even periodically, indicates serious problems already in the mechanical part of the automatic transmission, and there is only one way out - repair. Sometimes you can hear the statement that the cause of all troubles can be a clogged oil filter in an automatic transmission. Like, replace the filter, change the oil twice - and all problems will disappear. That doesn't happen. The process of destruction of friction elements is irreversible. Burnt clutches are treated only by replacing them, new oil is not able to restore them.

What is the difference between "hydraulic" and "electronic" automatic transmissions?

The automatic transmissions themselves are the same both in the first case and in the second. The main difference concerns the control system. The control system can be conditionally divided into three parts: generating status signals for the automatic transmission and its controls; analytical and executive. In the case of a "hydraulic" automatic transmission, the hydraulics ensure the performance of all these three parts by generating the appropriate pressures.

In the case of an electronic automatic transmission, all signals (input and output) are generated electrically, and hydraulics are used only at the end of the chain of control signals. In addition, an electronic control unit (computer) is used to analyze the incoming information and make a decision. This makes it possible to make the automatic transmission control system more flexible, providing automatic transmission operating modes that are inaccessible to the hydraulic control system.

What are codes? Why is the "OD OFF", "Hold", "S" or "Check AT" light flashing? Why are there no gear shifts?

Here we will talk about automatic boxes with an electronic control system. The operation of "electronic" automatic transmissions is controlled by an on-board transmission computer, which can be made either as a separate device or combined with an engine control unit. The transmission computer receives signals from various sensors (speed, throttle opening angle, high pressure hose position, automatic transmission oil temperature, etc.) located both in the automatic transmission and outside it. It processes this information and, based on its analysis, generates commands (output signals) to actuators in the automatic transmission (solenoids). Thus, the operation of the automatic transmission is controlled.

The computer also performs another function - monitoring and diagnosing faults. For all input signals there are admissible limits of their change. If any signal goes beyond the permissible limits, then the computer writes to memory a certain sequence of numbers - a code (Diagnostic Trouble Code - DTC) corresponding to this malfunction. In addition, the computer controls the resistance of the output circuits (or the currents flowing through them, which is the same thing). For them, there are also permissible limits, when they are exceeded, the corresponding fault code is written to the memory.

In addition, the computer can compare the readings of the speed sensors of the input and output shafts of the automatic transmission, thereby controlling the gear ratio of the automatic transmission. Deviations of the calculated gear ratio from the given one is a sign of slippage in the automatic transmission friction controls, which is also fixed by the corresponding codes in the transmission computer memory. Unfortunately, the gear ratio control function is not implemented in all car models.

To read the codes in the computer's memory, special diagnostic equipment is required - a scanner. The scanner allows not only to read codes, but also to erase them, and it can also be used to determine the readings of various sensors of the automatic transmission control system. The procedure for reading and identifying faults by codes is often called computer diagnostics.

What happens after a fault code appears in the transmission computer memory? This is determined by the algorithm of the program on which the computer works. The reaction of the control system is ambiguous. When some codes appear, no tangible changes in the operation of the transmission will occur, while other codes may cause no gear changes. It all depends on which circuit of the control system failed. Some codes are informational in nature (for example, the code "the battery was disconnected"), while others lead to a change in the algorithm of the automatic transmission control system (for example, the code "break in the solenoid circuit").

In the event of serious problems, the control system switches to automatic transmission protection mode. This emergency mode has different names: Limp In, Limp Home, Safe Mode, etc. The operation algorithms of the control system in emergency mode are largely determined by the automatic transmission model. In some cases, the control system stops monitoring the quality of switching, and they occur with "bumps". In other cases, the box engages the second or third gear, and all gear changes are prohibited. In some cars, the emergency mode is accompanied by a flashing or a constant indication on the instrument panel of one of the signals associated with the operation of the automatic transmission: "Hold", "S", "Check AT", "OD OFF", etc.

In the case of a combined engine-transmission computer, this signal can be "Check Engine", or a symbol in the form of an engine outline. If none of these signals on the panel is lit, then this does not mean that there are no trouble codes in the computer's memory, but if there is a signal, then there are codes in the computer's memory. The emergency mode does not involve the operation of the car, it serves only to get to the service and fix the problem. If this is not done, then it may turn out that due to a minor malfunction that was not fixed in time, the entire automatic transmission leaves.

It must be borne in mind that the "electronic" box, in fact, is an actuating device. Problems with gear changes, poor dynamics, jerks, "bumps" can be caused both by a malfunction of the transmission itself, and by problems with wiring and sensors, as well as by a faulty transmission computer. Problems in the on-board electronics lead to the failure of the box itself, after the repair of which the situation will most likely repeat itself. And so on until the cause of the malfunction of the electronic part of the control system, which is not always located in the automatic transmission itself, is eliminated.

As a rule, cars arriving for repair have not one, but a whole range of faults. Qualified diagnostics will help to understand this tangle of problems. But one should not expect miracles from the diagnosis, although sometimes it is possible to quickly fix the problem and the box "comes to life" before our eyes. The possibilities of diagnostics have objective limitations. Computer diagnostics is far from equivalent for different types of automatic transmissions. Its capabilities can be assessed by looking at the full list of codes for this automatic transmission model. For some models, the list of all possible codes (and hence controlled parameters) consists of four items, while others have fifty.

What are adaptive automatic transmissions?

Again, this term refers more to the control system, and not to the automatic transmission itself. The development of "electronic" automatic transmissions has led to the emergence of adaptive gearboxes. The developed control algorithms are becoming more and more intelligent, which leads to the emergence of a new quality in the same, from a mechanical point of view, transmissions. The on-board computer monitors the driver's driving style, adjusting accordingly. In addition, the algorithm of operation of such a computer takes into account the wear in the automatic transmission of friction controls. All this leads not only to an increase in the comfort of a car trip, but also to an increase in its resource and efficiency.

What is Autostick (Steptronic, Tiptronic)?

This is an automatic transmission control system, in which, along with automatic, a semi-automatic control mode is also provided, in which the driver gives the command to shift gears, and the quality of these shifts is ensured by the control system. Depending on the manufacturer, this mode has different names (Autostick, Steptronic, Tiptronic), it is implemented only on cars with an electronic automatic transmission control system, and even then not on all.

In cars equipped with such a system, the RVD has a special position in which the Autostick mode is activated. Regarding this provision, there are two opposite, non-fixed provisions of the WFD. These positions are labeled "+" ("Up") and "-" ("Dn"), respectively, for upshifting or downshifting. The Autostick mode is semi-automatic rather than manual, as transmission computer, does not cease to control the actions of the driver and will not allow him, for example, to move from a higher gear, or to select a gear in such a way that the engine speed exceeds the allowable one. Otherwise, the complete illusion of a mechanical transmission. At the request of the driver, you can also switch to the normal automatic control mode by moving the high pressure hose to position "D".

automatic transmission in winter.

So. Automatic transmissions work perfectly and are extremely reliable in all seasons except winter. Therefore, I tell you how not to plant the automatic transmission if the temperature is below 15 degrees.

1) It is necessary to warm the car to WORKING! temperature. The oil cooler of the box and the engine is the same, and the box is farther from the engine, so the automatic transmission warms up LATER.

2) If you really can’t bear it, warm it up to at least 40, and then on the go, turning on 3rd gear and at a speed of no more than 40 km / h to working.

3) Before winter, change the oil and filter. The elementary truth - but the result is by no means elementary - saving money on repairs. Now, what will happen if this is NOT done.

In the automatic transmission control system ("brains") there are a number of valves, consisting of plastic and springs, which open from pressure. With thick oil, the pressure is higher and the plastic, if you rev ​​with a slip, breaks. Consequence - a spring with fragments of plastic flies further and wedges the gears. Since the on / off drive gear is also made of plastic, it breaks. The result - the box does not shift gears either above 2, or quickly shifts from 2 to 4. If you ride like that, the clutches and repairs are planted in full.

For those who like to do everything themselves, I would generally advise reducing the working pressure by half a turn before winter.

based on ka.poehali.net