Signs:
The car either does not move at all or constantly slips (there is no acceleration at increasing engine speeds), automatic transmission malfunction or the complete absence of switching, noise from the machine, etc.
Diagnostics:
Primary - removing the pallet from the automatic transmission and inspecting it for the presence of metal and other foreign fractions in it (chips, metal dust, plastic fragments, etc.). Inspection of the oil in order to detect whether or not there are particles of antifreeze, air, combustion products and other damage in it. This is followed by an analysis of the machine for a thorough visual examination of each individual part in order to identify various kinds of damage. It is also done with the help of a scanner, but due to the fact that such an inspection can give errors, the output, as a rule, will be inaccurate.
How to check the oil in an automatic transmission In most cases, it is located under the hood, but in modern cars it is increasingly practiced to "hide" it in order to exclude cases automatic transmission breakdowns associated with the human factor. So there is no need to look for it and blame the manufacturer and / or the previous owner for this, everything is much simpler - the installation of a stationary probe on certain types of automatic transmissions is not provided. If not, you need to use the universal service probe. But! On some cars, even a universal service probe is not provided, but can be carried out strictly in specialized service centers. In order to know for sure the peculiarity of your automatic transmission, we recommend on our website.
Malfunctions of the torque converter: Violation of the tightness of the piston seal and failure of the main locking clutch. Destruction of the turbine, overrunning clutch, blades, breakage of drive splines, etc.
Signs:
The car does not move and slips at any of the speeds. Noises and crackles are heard from the front of the box. Only fifth gear is missing.Diagnostics:
" Blocking error"Can issue electronic diagnostics with a scanner. On automatic transmission magnets, hedgehogs are made of steel dust and small chips, friction dust in the pan.
Torque converter device
Hydraulic plate (hydroblock) with its mechanical problems.
Signs:
Hard and protracted shifts, bumps and sometimes no shift to one of the overdrives.
Diagnostics:
The scanner in this case rarely gives the correct result, here it often only helps to completely disassemble the unit and inspect the fur. Plungers in order to detect burrs and wear on them, it is also necessary to inspect the valves and balls for wear and check the spring elasticity parameters.Finally, it should be noted that only an experienced specialist is able to accurately determine and eliminate any defect in your automatic transmission.
An automatic transmission (abbreviated as automatic transmission) is one type of vehicle transmission. The automatic gearbox independently (eliminates the direct intervention of the driver in the process) sets the desired ratio of gear ratios, based on driving conditions and various factors.
Engineering terminology recognizes as “automatic” only the planetary element of the assembly, which is directly related to gear shifting and, together with the torque converter, creates a single automatic stage. An important point: automatic transmission always works in conjunction with a torque converter - it guarantees the correct operation of the unit. The role of the torque converter is to transfer a certain amount of torque to the input shaft, as well as to prevent jerks when changing stages.
Options
Automatic transmission is, nevertheless, a conditional concept, because there are its subspecies. But the ancestor of the class is a hydromechanical planetary gearbox. It is the hydraulic machine that is associated with automatic transmission, for the most part. Although currently there are alternatives:
- robotic box ("robot"). This is a variant of "mechanics", but switching between stages is automated. This is possible due to the presence in the design of the “robot” of electromechanical (electropneumatic) actuators, which are driven by electronics;
- variable speed drive. A subspecies of a continuously variable transmission. It is not directly related to gearboxes, but implements the power of the power unit. The process of changing the gear ratio occurs gradually. The V-chain variator has no steps. In general, the principle of its operation can be compared with a bicycle speed sprocket, which, as it unwinds, gives the bicycle acceleration through the chain. Automakers, in order to bring the operation of this transmission closer to traditional ones (with steps) and to get rid of the mournful hum during acceleration, create virtual gears.
Device
The hydromechanical gearbox - "automatic" consists of a torque converter and an automatic planetary gearbox.
The design of the torque converter includes three impellers:
Each element of the gas turbine engine (torque converter) requires a strict approach in production, synchronous integration, balancing. Based on this, the gas turbine engine is manufactured as a non-separable and non-repairable unit.
The constructive location of the torque converter: between the transmission housing and the power plant - which is similar to the installation niche for the clutch on the "mechanics".
Purpose of gas turbine engine
The torque converter (relative to a conventional fluid coupling) converts the engine torque. In other words, there is a short increase in traction, which is received by the box - "automatic" when accelerating the vehicle.
An organic drawback of the gas turbine engine, following from its principle of operation, is the rotation of the turbine wheel when interacting with the pump wheel. This is reflected in energy losses (the efficiency of the gas turbine engine at the time of uniform movement of the car is no more than 85 percent), and leads to an increase in heat emissions (some torque converter modes provoke a greater heat release than the power unit itself), increased fuel consumption. Now automakers on their cars integrate a friction clutch into the transmission, which blocks the gas turbine engine at the moment of uniform movement at high speed and higher stages - this reduces friction losses of the torque converter oil and reduces fuel consumption.
What is a friction clutch for?
The task of the clutch package is to switch between gears by communicating / disengaging parts of the automatic transmission (input / output shafts; elements of planetary gearboxes and deceleration in relation to the automatic transmission case).
Coupling design:
- drum. Equipped with the necessary slots inside;
- hub Has outstanding external teeth of a rectangular shape;
- set of friction discs (ring-shaped). It is located between the hub and the drum. One part of the pack consists of metal outer lugs that fit into the drum splines. The other is plastic with internal cutouts for the teeth of the hub.
The friction clutch communicates by compression by an annular piston (integrated into the drum) of the disk set. Oil supply to the cylinder is carried out using drum, shaft and body (automatic transmission) grooves.
The overrunning clutch has free slip in a certain direction, and in the opposite direction it is wedged and transmits torque.
Overrunning clutch includes:
- outer ring;
- separator with rollers;
- inner ring.
Node task:
Automatic transmission control unit: device
The block consists of a set of spools. They control the oil flow towards the pistons (brake bands)/friction clutches. The spools are arranged in a sequence that depends on the movement of the gearbox/automatic selector (hydraulic/electronic).
hydraulic. Applies to: oil pressure of the centrifugal governor that interacts with the output shaft of the gearbox / oil pressure that is generated during the depressing of the accelerator pedal. These processes transmit to the electronic control unit data on the angle of inclination of the gas pedal / speed of the car, followed by the switching of the spools.
Electronic. Solenoids are used to move the spools. The wire channels of the solenoids are located outside the automatic transmission housing, and go to the control unit (in some cases - to the combined control unit for the fuel injection and ignition system). The received information about the speed of the car / angle of inclination of the gas determines the further movement of the solenoids through the electronic system / the handle of the automatic transmission selector.
Sometimes the automatic transmission works even with a faulty electronic automation system. True, provided that the third gear (or all stages) is on in the manual mode of controlling the box. 
Selector control
Varieties of the position of the selectors (automatic transmission lever):
- floor. The traditional location in most cars is on the central tunnel;
- stalk. This arrangement is often found in American cars (Chrysler, Dodge), as well as in Mercedes. The desired transmission mode is activated by pulling the lever towards you;
- on the center console. It is used on minivans and on some conventional cars (eg: Honda Civic VII, CR-V III), which frees up the space between the front seats;
- button. The layout has been widely used on sports cars (Ferrari, Chevrolet Corvette, Lamborghini, Jaguar and others). Although it is now being integrated into civilian vehicles (premium class).
Slots of floor selectors are:
Box operation
How to use the box - "automatic" correctly? Two pedals and many transmission modes can plunge an inexperienced driver into a stupor. At first glance, everything is simple, but there are nuances. Below are explanations of how to use the automatic transmission correctly.
Modes
Basically, the “automatic” box has the following positions on the selector:
- P is the implementation of the parking lock: blocking the drive wheels (integrated inside the gearbox and does not interact with the parking brake). An analogue of setting the car into gear ("mechanics") when it is parked;
- R - reverse gear (it is forbidden to activate while the car is moving, although blocking is now applied);
- N - neutral gear mode (activation is possible during short parking / towing);
- D - forward travel (the entire gear ratio of the box is involved, sometimes two higher gears are cut off);
- L - activation of the low gear mode (low speed) for the purpose of driving off-road or on such, but with difficult conditions.
Auxiliary (advanced) modes
Present on boxes with extensive operating ranges (the main modes may also be labeled differently):
- (D) (or O / D) - overdrive. Economy mode and measured movement (whenever possible, the box switches to the top);
- D3 (O / D OFF) - deactivation of the highest stage for active driving. It is activated by braking by the power unit;
- S - gears spin up to maximum speed. There may be the possibility of manual control of the box.
Take into account:
The “automatic” with respect to the manual gearbox slows down the engine only in certain modes, in the rest, the transmission has free slip through the overrunning clutches, and the car “freewheels”.
Example - manual transmission mode (S) provides for motor deceleration, but automatic D does not.
While driving
How to use the "automatic" box correctly in the direction of travel? Modern transmissions allow the transition from one mode to another without pressing the button on the selector lever (except R). And in order not to prevent the arbitrary start of the movement of the machine during a stop, you must press the brake pedal when switching modes.
You also need to know how to properly tow a car with automatic transmission. You must adhere to the following recommendations:
- check the oil level in the box for compliance with factory standards;
- turn the ignition key, remove the lock from the steering column;
- switch the selector to N mode;
- towing is recommended no more than 50 kilometers, at a speed of 50 kilometers per hour, and less. When stopping, it is desirable to cool the box;
- it is forbidden to start the engine while towing.
An unremarkable building on a site with cars, a door, a staircase, a dark corridor, a basement, a door again ... First of all, you find yourself in "purgatory" - a small room like an airlock that separates this world, with racks of grubby and "dead" automatic transmissions, and that one is mysterious and sterile.
I’ll make a reservation right away that any attempts by motorists to enter ZF directly will not be successful. The concern works only with official dealerships and car services that rent automatic transmissions for industrial restoration.
How is it different from repair? The fact that not only a worn or broken part changes, but also all the rest, the parameters of which differ from the new ones. Sometimes only the body and some parts with a long service life remain old.
We did not have warranty cases for ZF automatic transmissions. All those who came to us either worked out their resource, which happens infrequently (on bench tests it is about a million kilometers, to match the engines, in Russian operating conditions, about 250-500 thousand), or failed due to the fault of the car ownerOleg Molotkov
Time has gone
A failing gearbox, or "cor" as it's called here, goes through several stages to enter the world of micron tolerances. At the first, it is washed with an alkaline solution in a special device resembling an air grill.
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Then, with the help of a special hoist, they are moved to the sandblasting chamber. It is with inner gloves - a similar design is used to work with radioactive elements. Only the sand in the chamber is not quartz, but plastic. The hands of a mechanic who has received an order for the restoration of the unit and 7 hours of time for the entire process move the nozzle of the supply hose with a sand-air mixture over the casing of the automatic transmission. A couple of minutes, and the case looks like new. Another wash, and the "patient" on a special cart is sent to the "debriefing" and resuscitation.
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There are five ZF industrial recovery centers in the world, one of which is in Russia. Moreover, it works for all countries of the Customs Union, and sometimes for far abroad countries. There is not a single mechanic in the center who has ever repaired gearboxes in Russia. All of them were recruited without experience, with the usual technical education and trained in Germany. It is believed that retraining our "specialists" is very costly.
All errors, including overheating and slipping, the time and conditions for their occurrence, are recorded in the mechatronic control unit of the automatic transmission. But it is impossible to “read” this data either with Chinese multi-brand scanners or with all sorts of VAG-coms - only with a dealer or factory scanner. The latter is more functional.
If the error was simply deleted using a dealer scanner, then this is immediately clarified through viewing the backup. It is also immediately clear whether the mechatronics is “native”. It determines the mileage of the box, and depending on this, certain parts change.
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After a few minutes, graphs and tables appear on the monitor. The diagnosis is manually entered into the troubleshooting sheet, and the box is sent for disassembly. By the way, one of the most important parameters read is the automatic transmission version number. Only on it you can determine all the initial parameters.
The unit under study passed only 53 thousand km, but he was not lucky. In the clutch package D, the fluid pressure dropped, the electronics tried to rectify the situation, but to no avail. The adaptation process did not go well, as evidenced by both the numbers and the built graphs. They are the mechanic's guide to action. When disassembling, the D package will be examined with particular predilection.
So, the electronically defective box is disassembled, some of the parts are on the table, some are on a special rack that resembles a dishwasher basket. All clutches are arranged in order, like plates of a large dinner service.
The first task of the mechanic is to check the wear of the shafts and bushings on the input shaft and the gaps in the packages, on the basis of which, if necessary, adjusting rings are written out. The tolerance tables on the wall are a secret with seven seals, which is different for each automatic transmission version. On the dial of the micrometer in the hands of the master 1.92. Alas, it won't.
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And here is the “donut”, that is, a hydrodynamic transformer, or GDT for short. The modern "donut" is a hybrid of hydraulic and conventional friction clutches. We will not go into details of the design now - in detail. The friction lining tends to wear out and contaminate the oil with its residues.
And according to ZF technologies, the “donut” is not subject to repair at all. Sawing it, replacing the blocking lining and welding it back, followed by balancing, is a workable, but artisanal type of repair. According to the rules, it is supposed to be changed in the collection.
However, if the overlay is still “alive”, the gas turbine engine can be washed on the machine. But if, say, the clutches of the gearbox have the fifth, last degree of wear with the destruction of the metal, this will no longer help. Do not wash the shavings from the torque converter. In the meantime, the “donut” is hermetically fixed between clamps through which clean oil is supplied under pressure, and soon it turns out to be perfectly clean.
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While the gas turbine engine is “washed”, the mechanic studies the catalog of parts, choosing the parts needed for replacement, according to the troubleshooting sheet, and goes to the warehouse, where the assembled package of spare parts awaits him. Exceptionally original, of course.
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Installing them correctly and with the necessary clearances will not work without the ZF instruction diagram and a special tool: a variety of mandrels, keys and other pieces of iron, the names of which cannot be picked up the first time.
It seems that everything, the automatic transmission is assembled and can be considered restored, but this is only for a non-professional look. Another tal carries her to a table next to a water-filled aquarium, only without fish. Swimming for tightness is another test. Compressed air is supplied through the fitting inserted into the technological opening of the housing, and the "machine" slowly dives under the water. If there are no bubbles on the surface, drying is ahead and the next test, if there are, again for disassembly.
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But this practically does not happen, with the exception of the story when the dealership could not find a place where fluid leaked from the case. A defective gland was found just in this aquarium.
The same process goes through factory testing and new automatic transmissions. The transmission after restoration must have all the characteristics and resource, as well as just left the factory. The requirements of Jaguar, Land Rover or BMW, which use ZF transmissions, are very high, so our task is to fully meet them.Oleg Molotkov
General Director of LLC "CF Russia"
Then the automatic transmission is sent for new tests on a stand that simulates the operation of the engine. The control unit of the box is connected via the Internet to a remote ZF server, and, based on the number read, the most up-to-date software for the test is uploaded to it. Then the stand simulates all possible engine modes, with which the “automatic” must perfectly cope.
The mechanic cannot intervene in the process, as well as set its parameters. But if he suddenly hears extraneous noise, unusual for the unit, he is obliged to stop the test and send the unit for rework. The result of an impartial examination is printed out and applied to the restored unit.
The very last stage is the firmware of the mechatronics with the "binding" of the automatic transmission to a specific engine. However, "registration" can be done on dealer equipment.
How not to get in?
Is there a chance not to get to the restoration of the automatic transmission at all, and drive happily ever after? First, it is worth keeping an eye on the car as a whole. First of all, behind the cooling system, because the automatic transmission does not tolerate overheating.
Secondly, in the box you need to change the oil. At least once every 60,000 kilometers. In detail, and now we once again received confirmation from the manufacturer. An oil change is required.
Thirdly, you need to drive carefully. Wear is accelerated by sudden acceleration (especially in cold oil), towing and slipping in the mud. These are all common truths.
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By the way, how much does such an automatic transmission repair cost? No one will give you a specific figure in ZF. It all depends on how much the "machine" was ruined and the margin received by the intermediary firm or dealership. However, it is believed that for 30 thousand rubles, a qualified craftsman will only agree to disassemble the box, rinse it and assemble it again. And then, as the card falls… Diagnostic, of course.
Box welding gears with "argon", whether it be a manual transmission or an automatic transmission, is the most affordable and most acceptable, and often perhaps the only option that allows the car owner to simultaneously save not only the "family budget", but also more expensive - "time" spent on repairs. One of the significant aspects influencing the choice in favor of welding is the final price of locksmith and welding work, because welding makes it possible to eliminate the “defect” itself, even without dismantling the gearbox from the car.
Of course, we exaggerate the process of preparing and welding the damaged “unit” from the “slightly” part, there are plenty of factors influencing the need to remove the “box” from the car. The main ones are "character", the degree of damage and the possibility of welding directly "on the car". Of course, you should also take into account the "material" from which the housing (crankcase) of your gearbox is made. The most repairable boxes are made of aluminum alloys, which include a variety of silumins, magnalium and partially duralumins.
Finding trouble for your "gearbox", even without leaving such a metropolis as Moscow, is quite easy, and out-of-town trips increase the likelihood that you will have to look for a "gearbox or automatic transmission welding" service in the foreseeable future. As a rule, the lion's share of defects (which are subsequently "corrected" by welding) are mechanical damage. A crack in the gearbox in 99% of cases is the result of excessive load on the crankcase housing, and the reasons may be different.
The banal inattention of the car owner, this is the dominant reason forcing "clients" to come to our technical center (located in ZAO, SWAD Moscow), after the "meeting" of the box with a curb, fittings, pit and other construction or natural obstacles, cases of damage to the box during Accidents (in which the crankcase protection of the engine and gearbox are powerless). The mistakes of car owners - amateurs, when replacing the clutch on their own, lead to the fact that if the gearbox is incorrectly installed on the car, they manage to break the “ear” at the gearbox, and at best they only find a crack that has appeared near the gearbox mounting hole.
Gearbox welding - argon
First of all, specialized specialists determine the feasibility of using "argon welding", many damages are even perfectly "healed" by a two-component adhesive, provided that the necessary conditions are met and the result is guaranteed. Some defects on the "mechanical box" are treated condescendingly, because an insignificant transmission oil leak on them is not as dangerous as on automatic gearboxes ...
The most problematic, are considered defects that do not allow daily operation of the machine, these include:
Gallery - box welding"
- "Hole" in the gearbox - a through hole in the housing that does not allow you to stably maintain the required level of transmission oil (ATF oil);
- The gearbox has burst, the danger of a crack that has appeared lies in the fact that its formation (with the exception of an impact) “indicates” a malfunction of the gearbox itself (so the destruction of one of the output shaft bearings often leads to a crack on the gearbox housing on the clutch side), and "stress" in the metal can lead to further cracking. Argon welding without gearbox repair is ineffective in such cases;
- A piece broke off from the gearbox, only with the help of welding it is possible to put together a lot of broken fragments that form the crankcase of the box;
- The gearbox mount is broken, one of the most common defects, sometimes not allowing to fix the installed gearbox on one of the many "pillows" - mounting supports, which usually requires surfacing of the missing fragment (with or without "cutting" the threaded connection).
Box welding - technology
One of the advantages of our services is mobility, because it is much easier to "weld the box" in the car service you applied to than to remove it and bring it to us. We ask our customers to treat with understanding the request to send a photo of the defective area to Viber (Viber) or WhatsApp (WhatsApp), in turn, this will allow us to promptly orient you on the time and price of our service "welder on the road.
Some limitations when using welding equipment are accessibility to the damaged area and the possibility of restoration work without dismantling the gearbox. It is also worth considering the preparatory work, which consists in preparing the surface of the part to be welded, which is properly cleaned and degreased ...
Welding is carried out with welding equipment that allows welding aluminum-based alloys, such as silumin, magnalium and duralumin. Indeed, for the most part, gearbox housings are made from these alloys. Current strength and filler rod are selected individually for each box.
The task of the welder - argonist, is to eliminate the defect, ensuring the tightness and strength of the weld, without creating deformation of the product. Alas, the welding process itself is not so simple, the nuances of the correct choice of a tungsten electrode, the amperage of the welding current, the polarity of welding, the supply of argon to the arc formation zone, the choice of the filler rod brand and the professional "chameleon" are only 10% of success.
The remaining 90% of success depends on the experience of our welders, to heat the edges of the parts to be welded, but only a profile welder can prevent overheating of the metal, because overheating can lead not only to the formation of cracks in the weld, but also to the "boiling" of the aluminum alloy and, as a result, the appearance "bubbles" in the weld, and the porous structure of the weld weakens it...
Our main principle: if possible, it is better to do without welding. But if, nevertheless, it is impossible to do without welding, then it is necessary to provide:
- - strength (it should be no worse than that of a new part)
- - tightness (of the part itself and in conjunction with neighboring ones)
- - durability
- - restoration of geometric dimensions (may change after welding)
If this is not observed, then it is better not to undertake welding.
Based on our more than 14 years of experience, we can say that almost everything can be restored - the only question is financial feasibility and timing.
Examples of some of our work:
1. Welding of cylinder blocks (BC).
1.1. Repair of BC beds after turning the liners and in the event of cracks on the crankshaft bed supports.
The reason is a drop in oil pressure. Most often - on commercial vehicles with high mileage. As an example, let's take the most difficult case: damage to the bed of the business center of the Mercedes-Benz Sprinter minibus (OM 611 engine). After the appearance of a characteristic "tapping" of the engine, the car managed to make another 10 flights. As a result, the crankshaft broke after jamming, and one of the bed supports collapsed. At the same time, the liners in the remaining 4 supports turned ... Here's what happened in the end:
The bed is additionally reinforced by installing studs instead of bolts. The cost of work is 14,000 rubles.
Another common case is the cranking of the engine liners of a heavy-duty vehicle (any brand, including MAZ, KAMAZ). In this case, it is impossible to do without welding the support using a special material ...
It is much easier from the point of view of welding technology to restore the aluminum BC supports. Although the case with the BMW (M52 engine) was not so simple - the cracks on the bed came out from the top of the BC and passed through the partitions between the cylinders ...
The cost of all works is 55,000 rubles.
1.2. Welding holes and cracks BC
The most "heavy" losses are borne by the BC after an accident or when one or more connecting rods break. In this case, holes or chips of the block itself occur and it is most difficult to restore working capacity - after all, the associated parts also suffer. So, when eliminating a large hole in the wall of the block, we had to do a lot of related work ...
It is most difficult to eliminate cracks in the cooling jacket, and especially in "indigestible" cast-iron blocks. The following case is special: after welding, it was necessary to restore the performance of "wet" sleeves. So: the cylinder block of a Chinese truck - cracks in the partitions between the cylinders with damage to the belts, along which wet liners are sealed ...
Restoration of the landing of “wet” sleeves along the upper and lower (for rubber rings) mounting holes included: milling the mating plane of the BC, turning the supports for the sleeves to the same height (with an accuracy of 0.01 mm), repairing the sealing belts (welding, boring)
Restoration of the landing of “wet” sleeves along the upper and lower (for rubber rings) mounting holes included: milling the mating plane of the BC, turning the supports for the sleeves to the same height (with an accuracy of 0.01 mm), repairing the sealing belts (welding, boring)
All sleeves are adjusted to the height of the protrusion above the BC plane. The block is restored, the cooling jacket is pressed. The cost of all works is 52,000 rubles.
This section does not illustrate all cases of repair of cylinder blocks using welding, but only the most complex of them. We successfully eliminate other BC defects:
- - a crack along the oil supply hole to the crankshaft bed support - 7,000 rubles;
- - damage to the main oil channel of the BC (in case of a broken connecting rod) - from 2,000 to 7,000 rubles;
- - a break in the threaded bosses of the engine mounts - 1,500 rubles. for the boss;
- - a crack in the threaded well (the thread of the block head to the BC). The cost for an aluminum BC is 5,000 rubles;
- - damage to the docking plane of the BC (with the block head) - from 1,500 to 5,000 rubles.
We try to repair everything else, not using welding, but using our experience in metalworking.
