Operating temperature atf in automatic transmission. atf replacement cycles in automatic transmission

ATF is consumed not only in accordance with the mileage, but also depending on the operating temperature. There are potential temperature dependent mileage values ​​in the manner described below, so monitoring the ATF temperature is critical.

Ratio of ATF temperature to possible mileage:

• 80 ° С - 160,000 km.
• 90 ° С - 80,000 km.
• 105 ° С - 32,000 km.
• 115 ° С - 16,000 km.
• 125°C - 8,000 km.
• 145°C - 2400 km.
• 155°C - 1,280 km.

For reference:

• Range of normal temperature values: -25°С - 170°С
• Typical temperature value: 100°C
• Temperature values ​​in extreme conditions: 150°С
• Temperature value on the adhesion surface: 393°C

All of the above temperatures in the AT inevitably lead to deterioration of the ATF. In this regard, there is a need for ATF maintenance, which is different from engine oil maintenance. In addition, the mileage of the car depends on the type of settlement (for example, if it is a city with active and passive traffic cycles), on the season (for example, in the summer season there is an increase in engine speed in idle mode), on driving mode, on the type of drive , for example 4WD, so the degree of deterioration of ATF is different.

For example, it happens that a car at high speeds may stall, even if the gearshift lever is in position D. If this situation repeats several times while driving around the city, this indicates a deterioration in ATF quality - regardless of kilometers driven. For this reason, the ATF must be replaced and checked as soon as possible.

In vehicles such as 4WD vehicles where the temperature of the ATF rises rapidly, a specially built-in warning board (sometimes an indicator light) is used as a measure to lower the temperature, which lights up automatically when the temperature reaches a certain level.

When the display lights up, this indicates that the engine speed has increased, but the speed has remained low. It is in this situation that the temperature of the ATF rises greatly.

Situations when the board quickly lights up:

1. Slipping when driving on snow, sand
2. Driving at very low speed on a steep hill

In these and similar situations, engine speed will increase and if you continue to drive at low speed, the ATF temperature will continue to rise and the warning lamp will automatically illuminate. Stop the vehicle immediately in a safe place, move the gearshift lever to position P, but do not stop the engine. After a while, when the display goes out, you can continue driving. If after a while the display does not go out, do not take any measures yourself and contact the service center.

Points to pay attention to when changing the ATF

Procedure	What to look out for	Cause
	Be sure to use a paper towel.	To avoid the ingress of debris,
Checking with an indicator	Use the heating indicator (HOT), the car must be in a horizontal position.	To determine the actual amount of liquid
Checking with an indicator	Depending on the car model, it happens that the level mark on the indicator is difficult to determine, so skill is needed.	This is due to such a property of ATF as the degree of viscosity
Checking with an indicator	Honda - Within the first minute after stopping the engine	Feature of the system mechanisms
Checking with an indicator	Mitsubishi - Check in lever position N	In position P, the amount of liquid is different
	Do not operate with hose disconnected	To avoid debris
Checking with the ATF controller	Do not operate with debris in the hose	Not removed by cleaning
Checking with the ATF controller	Do not replace if the ATF is thick, milky white	High probability of failure
	Usually the hose is inserted to the length of the indicator + 10 cm	To avoid its penetration into the AT system There is a danger of chewing the tip
Replacement with an interchangeable device	Carefully check the amount of spent ATF on the indicator	To avoid excess / deficiency of ATF
Replacement with an interchangeable device	Honda - Carried out in manual mode - not in auto	Feature of the mechanisms of the system (there is a risk of damage to the gears)
Replacement with an interchangeable device	Mitsubishi - Carried out in manual mode - not in auto	Due to the characteristics of the oil pump - it takes time
Replacement Criteria	The first ATF replacement is carried out after 60-70 thousand kilometers. Approximately half of all fluid is replaced (with an 8-liter transmission - 4 liters)	If the ATF is replaced regularly, this will not cause any problems.
Replacement Criteria	The first ATF replacement is carried out after 100 thousand kilometers. ATF replacement prohibited	With a large mileage run, the output power of the engine is wasted on all mechanisms, and the balance is maintained with difficulty. With the replacement of ATF, revival occurs, rigid mechanisms jam, and malfunctions occur in the system.

I already touched on the abbreviation "ATF" a little in the article. But today I want to tell you more about it. We will analyze all aspects of the meaning, decoding, why it is categorically different from liquids in a mechanical transmission, how it works. Indeed, there are a lot of questions, there is even such a banal one - is it a liquid or is it oil? Let's figure it out...

Let me start with a definition.

ATF ( Automatic transmission Fluid ) - stands for automatic transmission fluid (automatic). It is used only in "torque converter" machines, also in some CVTs, it is practically not used in robots. It serves to lubricate internal components, as well as transmit torque from the engine - through the transmission - to the wheels.

I read on some forums - what is called the "blood" of the machine, because the liquid is really red.

Oil is not oil?

Let's start with the easiest question, what is oil or not oil at all? Guys, this is a liquid gear oil, it is much thinner than, say, manual transmissions. This is said by many features here, the torque is transmitted using a torque converter, and as we have already dismantled, high pressure is needed - flowing oil. Due to its high fluidity, it is customary to call it a liquid.

For example, gear oils for mechanics have viscosity tolerances and are divided into winter, summer and universal. Often you can see numbers like SAE 70W-85, SAE 80W-90, etc., choose for your weather conditions, but most now use universal ones.

There are no such tolerances on automatic machines! SAE viscosity does not apply to these fluids, they must always remain fluid in any weather, and they must also withstand much higher temperatures than their "mechanical" counterparts. ATF fluids include where there are large loads, this manifests itself in lubrication, protection of components from pollution and oxidation (rust), and also from overheating.

So the mechanics can warm up to 60 degrees Celsius during operation.

But the machine often works with temperatures of 90 - 110 degrees. For example, Chevrolet automatics can heat up to 120 degrees.

Therefore, cooling radiators are installed on the machines so that the oil does not burn at high temperatures. So it's oil, but it's not the same as the other two, mechanical transmission oil and engine oil.

Why bright red?

As we have already discussed from above, ATF oils are not like any other type of lubricant. And therefore it cannot be poured anywhere else, if you mix it up, there can be serious damage. And vice versa - if you pour the usual "manual transmission" into the machine. That is almost instantaneous death. And there were such cases, often they poured engine oil and after a few kilometers the automatic transmission got up.

To avoid such incidents, it was customary to paint the ATF red - that is, this is nothing more than just a difference, nothing more. Well, think for yourself, you will never pour red liquid into the engine, although anything can happen ...

How does it workATF fluid?

I have already touched on several aspects of the work from above, and now I would like to talk in detail about how it works.

Temperature

The average operating temperature of the liquid is about 80 - 95 degrees Celsius, although at some points, for example, in traffic jams in summer, it can warm up to 150 degrees. But why? It's simple - the machine does not have a hard transmission of torque from the engine to the wheels. Therefore, sometimes the engine gives increased power, which the wheels do not need to overcome road resistance - the excess energy must be absorbed by the oil and spent on friction, hence the heating in traffic jams is simply huge.

Foaming and corrosion

Large masses of oil that move under enormous pressure create a favorable environment for foaming ATF fluid. And in turn, this process leads to the oxidation of the oil itself, and metal parts. Therefore, the fluid must have the right additives to minimize these processes. Moreover, additives are selected each time different, there are no identical ATF oils. This is because the internal structure of automatic transmissions is different everywhere, in some devices there is more metal, in others there is metal - cermet, in others steel - bronze, this must be taken into account.

Liquid resource

As you understand, this liquid is essentially unique, it works in very adverse conditions, but even at such temperatures it can work for many thousands of kilometers. Its resource is approximately 50 - 70,000 kilometers. However, do not forget that it is not eternal, and after 70,000 kilometers its properties are lost, replacement is required.

Evaporation

Not many people know, but ATF oils can volatilize, so some manufacturers install dipsticks (to measure the level) on their machines. The level may drop due to the removal of vapors through the ventilation system of the automatic transmission cavities, in simple words, through the “breather”. Therefore, it is important to monitor the level, this is a kind of mandatory practice.

Why "ATF is so expensive

But really, why can a liter reach a price of 700 - 800 rubles, and a machine often needs about 8 - 10 liters? But as you understood from above, this is the most technologically advanced liquid, and it evolves every year.

It is much more perfect than motor oil, and even more so than ordinary gear oil, hence the prices. However, again, I repeat, it works in an aggressive environment and for a fairly long period of time, 60 - 70,000 kilometers.

Here it is ATF oil, I think you liked the article. Read our AUTOBLOG, subscribe to updates.

To fully understand this issue, you need to go from afar. Consider what oils are generally used in cars, how they fundamentally differ. Without going into details, these are engine oils, transmission (gear) oils, hydraulic booster oils, ATF and brake fluid. The similarity of all these oils, firstly, is that they are based on hydrocarbons obtained by processing fossil hydrocarbon raw materials, which, accordingly, gives some similarity in properties. All of them have a lubricating, slip-increasing between friction surfaces and a hydrorobic (repelling down) effect, as well as the ability to remove heat. A bit similar in appearance: oily to the touch with similar ones in the first approximation, this is where the similarity in properties ends.

This sometimes gives rise to irreparable errors when, for example, engine oil is poured into an automatic transmission, and brake fluid is poured into a hydraulic booster. Naturally, these actions are immediately followed by a breakdown of the unit. So how does ATF (Automatic Transmission Fluid) globally differ from all other substances poured into car devices.

ATF Properties

The fact is that ATF is the most complex fluid in a car, which requires a number of properties that sometimes contradict each other.

1. Lubricating effect: reduced friction and wear in bearings, bushings, gears, pistons, solenoid valves.
2. Increase (modification) of friction forces in friction groups: reduction of slippage (shift) between clutch pack frictions, brake bands, torque converter blocking.
3. Heat removal: rapid removal of heat from the friction zone due to thermal conductivity and fluidity.
4. Foam suppression: no foaming in air contact areas.
5. Stability: no oxidation when heated to a high temperature and in contact with atmospheric oxygen for the longest possible time.
6. Corrosion resistance: prevention of corrosion formation on the internal parts of the automatic transmission.
7. Hydrophobicity: the ability to expel moisture from serviced surfaces.
8. Fluidity and hydraulic properties: the ability to maintain stable fluidity and hydraulic properties (degree of compression) in a wide temperature range from -50 C to +200 C.

So what should be poured into the automatic transmission and how to top up ATF if the required ATF brand is not at hand or it is generally unknown what is filled in the automatic transmission?

To simplify the answer, we first make a few assertions.

1. Any type of ATF - mineral water, semi-synthetics or pure synthetics are mixed together without any negative consequences. More modern ATFs have better performance and properties.
2. The addition of a more modern type of ATF to a less modern type improves its properties.
3. The less modern ATF, the worse its properties and therefore it must be changed more often, but even the most dense ATF of the DEXTRON II type will work with the most modern automatic transmission of the ZF6HPZ6 type without any problems. Proven in practice!
4. No manufacturer discloses complete information about the composition and properties of the ATF they produce, limiting themselves to general advertising recommendations. The exception is special highly modified oils, in which their manufacturers do not know what they have mixed and promise a fantastic effect. Such liquids, if there is a desire to use them, are best poured without mixing with anything, since the effect is unpredictable.
5. Manufacturers' guidelines for the use of ATF in their products are largely driven by the goal of increasing profits and are not always technically justified.
6. It is desirable (but not necessary) to use ATF with constant frictional properties for automatic transmissions with hard torque converter lock-ups, and ATF with variable functional properties for automatic transmissions with mains lock-up having a controlled slip mode, the rest is not important.
7. All pieces of iron, gears, bearings, clutches, seals, etc. in automatic transmissions they consist of materials of the same properties, regardless of the manufacturer of the automatic transmission, the nuances are not very significant, which means that different ATFs cannot have fundamentally different properties.

Summarizing all of the above, we draw the following conclusion: if you fill or change ATF in an automatic transmission as a whole, it is advisable to use a more modern and apparently more expensive ATF, taking into account only its frictional properties (variable or constant) for your automatic transmission. If the budget is limited, then you can fill in any ATF that is suitable for the price - this will not noticeably affect the operation of the automatic transmission, but the ATF will have to be replaced more often. Manufacturers' recommendations can be ignored at all. When pouring ATF into an existing liquid, if the same brand is not available, it is necessary to use a liquid with a class not lower than the main one, i.e. DEXTRON III. It is possible to add DEXTRON II, but vice versa, it is undesirable, because if you reduce the properties of ATF in the original automatic transmission, it may start to work worse, if you don’t know what is filled in at all and are afraid to do harm, add the most expensive modern ATF type DIV-DVI, again in friction properties.

ATF Composition

Due to the need to obtain such a large number of multidirectional properties, the composition of ATF is extremely complex and is not disclosed in detail by the Manufacturers. In open information, there are only general data on the chemical and molecular composition of the main additives, it is these additives (additives) that ultimately form the set of properties that ATF should have, detailed formulas of substances and their interactions are classified.

The chemical composition of ATF consists of two main parts - this is the base base and the additive package. The base base is the directly carrier fluid that makes up the main volume. According to its type, the base is divided into three main groups: mineral, semi-synthetic and synthetic. A mixture of mineral and synthetic bases is also used, which is sold as synthetic. Mineral bases include paraffinic (paraffinics) and naphthenic oils, their group in the classification systems XHVIYAPI ATIEL (the tehnical association of the european lubricans american petrolen Institute). Semi-synthetic or conditionally synthetic include hydrated (hidroisomerised) mineral base oils, which are considered improved, but relative to the first group, their VHVI classification, one of the Yubase brand names. But the true synthetic base group is the polyalphaolefin HVHVI (PAD) oils. The technology for their production is extremely complex and expensive at the moment, and in most cases commercially available synthetic ATFs consist of part of a synthetic base with the addition of a mineral or conditionally synthetic base component, which you will never be notified on the packaging.

GATF additives

The second part of the chemical composition of ATF is the additive package. Their chemical composition is also classified by manufacturers, and in the public domain there is information on the general chemical composition and percentage of ions of various substances: phosphorus - P +, zinc - Zn +, boron - Bo, barium - Ba, sulfur - S, Nitrogen, Magnesium, and etc.

In fact, these ions are part of polyesters, which in the mixture create additional chemical compounds, enhancing certain properties of additives.

That is why we are always talking about an additive package with certain characteristics.

Consider the ionic composition of the additive package of the most common DEXTRON III / MERCON ATFs. The total amount of additives in DIII in relation to the base oil is 17%, of which in the composition of ionizers:

• Phosphorus - 0.3% AW in 2-ethyl-hexyl-phosphoric acid, improves anti-wear properties in the ZDDP additive.
• Zinc - 0.23% as part of ZDDP zinc diethyl dithiophosphate - antioxidant properties, anti-wear.
• Nitrogen - 0.9% AW additive (Anti-Wear)
• Boron - 0.16% AW additive, enhances cleaning properties by enhancing ZDDP.
• Calcium - 0.05%, in the composition of calcium phenolates - a washing effect, plus a dispersant in the composition of the base additive TBN, anti-corrosion effect.
• Magnesium - 0.05% detergent properties as part of the base additive, acidity reduction, anti-corrosion effect.
• Sulfur - 0.55% AW additive, plus in the composition of friction modifiers (FM), anti-wear properties in the composition of EP.
• Barium - various%, partial late control.
• Siloxane - 0.005% active defoamer.

The following ions are part of additives that have complex formulas, the details of which are classified, some of their names and the general chemical formula:

• ZDP - zinc phosphate, anti-corrosion effect
• ZDDP - - dithio-phosphate, antioxidant, anti-corrosion.
• TCP - tricresyl phosphate, heat resistance enhancement.
• HP - chlorinated paraffin, high temperature resistance.
• MOG - glycerin monoplast
• Stearic acid
• PTFE - Teflon (almost never used in ATF)
• SO - sulfated EP (Extrime Pressure Additive) stabilizes properties under excess pressure.
• ZCO - zinc carboxylate, corrosion inhibitor.
• NA is a group of alkylated benzenes.
• POE - ethers.
• TMP – lineoleic ether polynols
• MODTP

In total, about a hundred such additives have been developed, and one package of additives can include up to 20 complex substances that, when combined, give a cross effect that creates the desired characteristics for ATF.

History of ATF creation

Experiments on the creation of automatic transmissions began in droves in the 20s of the 20th century, but in those days no one seriously thought about changing the properties of the hydraulic fluids used in them. The first big breakthrough came in 1949, when General Motors introduced the world's first serial development of ATF, designated Type A. It was based on petroleum mineral oil, and sperm whale spermaceti was used as the only additive. Sperm oil was secreted from the unfortunate animal by a special gland and accumulated in two bags located in the depressions between the bones in the upper part of the skull. These sacs served as resonators for the whale's ultrasonic signals. After killing and butchering the whale, the spermaceti fat was frozen from the contents of the spermaceti sacs and hydrated, resulting in a substance called Cetin, the chemical formula of which is C15H31COOC16H33, which was used as the main component of the first ATF.

The quality of ATF Type A turned out to be so high that the mixture practically did not require any modifications, based on the fact that at that time the transmissions were low-speed, and the operating temperature did not exceed 70-90 C. Over time, the power and torque increased, and the original Type A ceased to meet the requirements, as it oxidized at higher temperatures and foamed, unable to withstand high speeds.

The next in the development of ATF was the Type A Suffix A fluid created in 1957 with improved performance. For the first time, additives containing substances based on phosphorus, zinc and sulfur began to be used in minimal amounts (about 6.2%), which made it possible to improve the antioxidant and other properties of ATF.

After that, there was nothing new for ten years, and only in 1967 GM took the next step by creating ATF with index B. From that moment on, a classification called DEXTRON was introduced, and the liquid was called DEXTRON B. Its fundamental difference was that that a significant amount (about 9%) of substances based on barium, zinc, phosphorus, sulfur, calcium and boron was introduced into its composition, which can be called an additive package.

Unlimited chemical harvesting of whales brought them to the brink of extinction, and in 1972 the US government was forced to pass the Endangered Species of Animals and Birds Act, completely prohibiting whale hunting. ATF manufacturers have begun to have dark days. For several years it was not possible to find a replacement for spermaceti fat. When using the fluids left at the disposal of manufacturers, the number of automatic transmission failures increased 8 times in the United States, and the matter smelled like a disaster. It wasn't until the mid-1970s that International Lubricants, in collaboration with renowned organic chemist Philippe, developed a liquid synthetic wax ester called LIQUID WAXESTER, patented under the trademark LXE®, which made it possible to improve the required properties of ATF by an average of 50%. The resulting liquids even began to surpass ATF based on spermaceti in a number of characteristics. Based on this technology, in 1975 GM created DEXTRON II index C with an additive content of 10.5%. But it soon became clear that ATF turned out to be quite aggressive and began to cause corrosion of metal surfaces, so a year later DEXTRON II index D was created, which included additional corrosion suppressant additives. The next step in 1990 was DEXTRON II index E, which included viscosity stabilizers at low temperatures and stabilizers at high temperatures. In 1995, DEXTRON III became the crowning achievement of all creations, as part of which all modern requirements were taken into account and a complex package of additives was introduced. So far, GM has created the DEXTRON IV, DEXTRON V, and DEXTRON VI. In parallel with GM, in-house developers led a number of firms, such as Ford, who created a number of their own ATFs, united by the MERCON classification, Toyota's Tyret classification (DTT).

This led to a fair amount of confusion in the classification of oils and understanding their compatibility with each other and with the design of the automatic transmission. Therefore, over time, it was decided to tie all these standards to the GM-DEXTRON classification. Therefore, on most ATF packages of any company, you can see the inscription on the back of the annotation: “Analogue DEXTRON III” or “DIV”, etc.

What is the difference in the properties of ATF from different manufacturers. Determination of compatibility with the automatic transmission design.

I would like to note right away, no matter what worthy experts say, there is no fundamental difference in the properties of the most modern ATFs. If you go into details, then two main factors are taken as the criteria for difference:

1. Interaction of ATF with various types of friction materials.
2. Various characteristics of friction coefficients in the clutch of friction clutches of frictional properties (variable and constant coefficient of friction).

On the first point: There are about a dozen manufacturers of friction materials in the world, such as Borg Warren, Alomatic, Alto and others, each of which develops its own original compositions. The basis is usually a specially treated cellulose fiber (friction cardboard), in which various synthetic resins are added as a binder, and soot, asbestos, various types of ceramics, bronze chips, fiber composites of the type * and carbon fiber. Accordingly, it is believed that the manufacturer of the automatic transmission selects the type of ATF for the friction material used, selecting the optimal value of the shear coefficient between the clutches at full contact in order to minimize heat generation in the clutch packs. However, regardless of the difference in the composition of friction clutches, all developers use the same chain, therefore, high-quality friction clutches from native companies do not differ much in properties, therefore they react similarly to different types of ATF.

On the second point: The engagement parameters of the friction elements of the automatic transmission are determined by the coefficient of friction. Friction, respectively, is of two types:

• sliding friction that occurs when the friction elements come into contact until they are fully engaged;
• static friction, when the clutches come into a state of full engagement and become motionless relative to each other.

In addition to the clutches in the brake and drive elements of the automatic transmission, there is also a torque converter lock-up clutch, which, when switching from a hydrodynamic (due to the compression of fluids between oppositely located blades) mode of transferring the main torque to a hard one (when the lock is fully pressed against the body and the H / TR works as usual clutch on mechanics) gets the same set of friction effects. However, in G / T modern automatic transmissions of 6 or more steps, an intermediate mode has appeared, called controlled slipping of the lock (FLU - Flex Lock Up) for smoother and more comfortable shifting, when the pressure regulator with a high switching frequency applies and turns off the pressure that controls the lock, keeping it on the verge of slipping. Accordingly, all types of ATF are divided into two classes: with constant friction properties (Type F, Type G) and variable friction properties (DEXTRON, MERCON, MOPAR).

ATF with unchanged frictional properties has a fairly linear picture: as the friction clutch is pressed (slip speed decreases), the friction coefficient increases, and at the moment the friction clutches engage, it reaches a maximum. This gives the effect of clearly working out gears with the allocation of minimal correspondence.

Accordingly, there is a sense of switching effect. When using ATF with variable friction properties, at the initial stage of pressing the friction clutch, the coefficient of friction-sliding has a maximum value, but as they are compressed, it decreases somewhat, reaching again a maximum at full contact, but at this value, the static friction coefficient is much lower. This gives the effect of smoother and more comfortable shifting, but the amount of heat generated increases.

Possible consequences: If you fill in ATF with variable properties in an automatic transmission with a hard inclusion of g / t, this can cause an undesirable effect of slipping the lock. In the case of an unworn automatic transmission, the hydrodynamic transmission will maintain torque until it is fully engaged and nothing unpleasant will happen. In a worn or damaged automatic transmission with burnt locks and clutches, excess slip can aggravate the situation and cause fatal destruction. If, however, in an automatic transmission with controlled slippage of the lock, fill in ATF with unchanged frictional properties, this can cause a harder gear shift, but will not bring tragic consequences. From this we can conclude that it is possible to add ATF with modified friction properties to it, and it will work softer, and if there is a feeling that the automatic transmission is slipping a little more than necessary, you can fill in ATF with unchanged friction properties and it will work more clearly.

In conclusion, I can add that much more serious factors than the friction properties of oils that affect the operation of automatic transmissions are temperature conditions, the degree of wear of friction clutch surfaces and other devices and control components, and frost. Before these factors, differences in ATF properties become negligible. It makes sense to take them into account only if there are ideal operating conditions for a new car.

The latest development on the ATF market

A few years ago, the technologists of the petrochemical company AMALIE MOTOR OIL developed a universal synthetic ATF, which has no analogues in the world, has fantastic properties, which equally meets the requirements of all types of automatic transmissions. The fluid was called "Amalie Universal Synthetic Automatic Transmission Fluid", which made a real revolution in the US market, having received certification from all leading car and automatic transmission manufacturers. A new type of fully synthetic base and a state-of-the-art multifunctional additive package provide unsurpassed protection and stable performance when used in any type of automatic and robotic transmissions, hydraulic boosters and other hydraulic systems, regardless of manufacturer. It successfully replaces the entire line of DEXTRON, MERCON, transmission fluids from Chryster, Toyota, Caterpilar and other manufacturers. The fluid is recommended for use in heavily loaded automatic transmissions from manufacturers such as BMV, Audi, Land Rover, Mercedes, Mitsubishi, Toyota and any other vehicles of the American, European and Asian markets. Two years ago, this ATF appeared on the Russian market. For those car owners who have the means and do not spare them for the maintenance of their iron horses, this product is a real solution.