DIY 6t40 automatic transmission repair

In 2002, General Motors specialists, together with engineers from Ford, developed an automatic six-speed transmission. 6T45... This modification of gearboxes was installed on SAAB, Opel, Chevrolet and a number of other General Motors vehicles that are assembled in Korea, China and North America. One of the features of this modification of transmissions is its versatility and the possibility of using it on a car with an engine from 1.4 to 3.2 liters of volume.

This modification of the transmission has numerous varieties that are intended for use with engines of various displacement: 6T30, 6T40, 6T50, It should be noted that the gearbox is quite reliable and compact. The latter makes it easy to install it in a small engine compartment.

Automatic transmission 6T30, 6T40, 6T45 has the ability to manually shift gears and activate sport mode. Transmission operation is controlled by a variety of electronic systems that are responsible for the performance and structural integrity of the transmission. Diagnostics has been significantly simplified, which in turn allows minimizing the cost of repair work.

From service maintenance, it is necessary to highlight the manufacturer's requirements for changing the oil every 40,000 kilometers. This work is performed simultaneously with the replacement of the transmission filter elements. With proper experience, the car owner can independently change the oil in the gearbox.

The problematic place of this modification of automatic transmissions is the gaskets and oil seals, which quickly fail and begin to leak oil. That is why it is necessary to inspect the gearbox on a trestle or pit with a regularity every two months to detect oil leaks from the gearbox. If the requirements for changing the transmission oil are ignored, problems with the valve body may appear. It should be remembered that capital repair of automatic transmission 6Т30 / 6T40 is very complex and expensive.

On cars Chevrolet Cruze, Opel Astra J: automatic transmission is installed 6T30 and 6T40... Their advantage over other units is fuel economy, switching speed, adaptability. But we also have a number of childhood diseases and design features. The box allows you to "kick" and in acceptable manifestations this is normal. The 6T series itself has established itself as an automatic machine of average reliability (in comparison with other automatic transmissions). Already by 100,000 km, routine maintenance is often required, with the replacement of consumables, the 3-5-R gear clutch. Also, to eliminate problems, a reinforced spring disc is used in the future. Often already at 60-80 thousand km. the mechatronics (the brain of the box) is changing. During our long practice, we have studied all the diseases of this family and we can safely say that there are no insoluble problems for us regarding this series of automatic transmissions. Call us - we will definitely help.

The automatic gearbox of the General Motors 6T40, 6T45 family is a modern version of front-wheel drive transmissions. The gearbox is 6-speed and has been included in Chevrolet and Buick cars since 2007 with power units up to 3.2 liters. The assembly of the automatic box is carried out in Korean and Chinese factories.

The service life of the automatic transmission, according to the manufacturers, is 300,000 km. However, in practice, this device fails ahead of schedule, therefore it is required to periodically carry out high-quality repairs of automatic transmissions 6T40 and 6T45.

Repair of 6T40 and 6T45 automatic gearboxes requires certain knowledge and skills.

Our qualified technicians regularly repair the damage to this device. The services provided by our workshop are as follows:

• Diagnostics of damages using computerized equipment;
• Repair of automatic transmissions 6T45 and 6T40;
• Replacement of consumables;
• Updating related damaged items;
• Valve body repair 6T40;
• Renewal of engine oil;
• Major overhaul.

Each gearbox has its own weaknesses. The main faults in automatic transmission 6T40, 6T45 include the following damage:

• Solenoid wear and torque converter slip mode leads to frequent engine oil changes;
• Breakdown of the outer circlip;
• Wear of the reactor sun sleeve;
• Failure of the control unit;
• The developed channel of the valve body.

All these malfunctions lead to the fact that the gearbox malfunctions. And the factors of wear of component elements, as well as the 6T40 valve body are:

• Use of poor quality oil;
• Regular movement at higher speeds;
• Disregard for the rules and timeliness of oil changes;
• Use of low quality materials;
• Regular towing;
• Making mistakes during the last repair.

It is possible to determine the malfunction of the automatic gearbox and the 6T40 valve body if you pay attention to the presence of the following symptoms:

• The appearance of the corresponding error on the panel;
• The lever gets stuck when changing gears;
• The occurrence of vibrations;
• The appearance of extraneous noise;
• The engine "stalled" without the possibility of further starting;
• The oil has acquired a dark shade and a burning smell;
• The presence of oil stains on the body.

Based on the above signs, the driver may assume a breakdown. But the reliability of faults is established only in the service center using computer diagnostics.

Our qualified mechanics regularly repair 6T40, 6T45 automatic transmissions and 6T40 valve body. Using specialized equipment, specialists perform the following actions:

• Breakdown diagnostics;
• Dismantling the automatic transmission;
• Replacement of consumables;
• Elimination of traces of corrosion and dirt;
• Updating damaged parts;
• When dismantling the device, mechanics gained access to the valve body, so it can be replaced if necessary;
• Elimination of other malfunctions that prevent the transmission from functioning properly;
• Change engine oil if necessary;
• Installing the box in its place.

After all the work is done, you should send the car for a test drive. This is required to identify any remaining damage. However, practice shows that such problems did not arise.

Service centers that repair damage set high prices for repairing automatic transmissions 6T40, 6T45 and valve body 6T40. Since they believe that the procedure is complicated, and they also carry it out for a long time.

Our qualified mechanics repair the damage much cheaply and quickly enough. However, the cost of the service can be influenced by the degree of equipment wear and tear.

In the future, this will lead to failure of the transmission, as well as damage to the accompanying elements. Breakdown of equipment at the wrong moment will lead to an emergency on the road, as well as a traffic accident.

Elimination of such consequences will cost many times more in comparison with planned repairs.

When contacting our service centers, customers receive quality guarantees. Therefore, if a breakdown occurs again within the warranty period, we undertake to fix everything quickly and free of charge.

Also, the advantages of our service are:

• Professional mechanics with many years of experience;
• Availability of professional equipment;
• Fast terms of damage elimination;
• Using original spare parts and high quality oil.

Malfunctions of the automatic transmission and valve body cause a lot of inconvenience, therefore, in order to prevent malfunctions, it is important to follow the rules of operation and maintenance.

1. Timely pass MOT
2. Change engine oil regularly.
3. Respond quickly to signs of damage.
4. Use original spare parts.
5. Change aggressive driving style.

The specified list of rules will allow you to avoid unforeseen breakdowns. In addition, the rules will help to increase the resource of the 6T40, 6T45 automatic transmission and valve body.

The assembly of the box consists of several stages.

• assembly of the block of clutches and planetary gears
• oil pump assembly
• combining the halves of the automatic transmission
• valve body assembly

The caliper in our box is of the old style. Four rings. The assembly of a new drum 4-5-6 and 3-5 / Rev begins with the installation of rubber rings.

Next, the clutch piston is 4-5-6.

We put a block of springs 4-5-6 and a piston-holder in it. We squeeze the bag in a press with a snap and put a retaining ring.

Now the installation of the piston 3-5 / Rev and everything connected with it.

Along the way, we rotate all the bushings on a press with a tooling. And for the time it will take to overturn - soak the drum clutches 4-5-6 and 3-5 / Rev in a new and clean DEXRON-VI

After the clutch is saturated with new oil, we collect the clutch packs on the drum. We really need to start by installing the shaft 😉

After that, we take this very pribluda by the shaft and put the automatic transmission in the crankcase. And then, we throw packages and planetariums, like a children's pyramid)))

The process of installing the caliper is extremely gimmicky. And there are some nuances with the installation of metal rings. Therefore, I was busy assembling and did not take off much. As a result, we come to the upper retaining ring.

This is how the half of the automatic transmission is assembled that with clutch packs and a wheel drive differential.

Then we move on to the other half of the 6T40.

For her, we wash and assemble the oil pump housing. In it we repress the bushings, replace the oil seal and install a new oil filter.

At this stage, we connect the halves of the crankcases.

We proceed to flushing and assembling the valve body. It contains six balls. Places pointed with a finger.

The diameter of the ball is cunning to the point of disgrace. 6.33mm I don’t even know which bearing will have to be picked up in case of loss. Therefore, be careful 😉

Wash, clean, blow through and assemble the valve body.

We continue assembling it on the automatic transmission crankcase.

We put brains with a solenoid block on the valve body. And we connect three sensor connectors.

That's all. The 6T40 automatic transmission was disassembled, defective, new spare parts were purchased, then assembled and ready to be installed back on the car.

The next report I will add a video of her work on the machine. Let's calibrate and go for a ride.

Repair of any automatic transmission from 1 day

CVTs, DSG, torque converters, new and remanufactured automatic transmissions, spare parts

# 1 Post andogagra Apr 27, 2017 2:03 pm

# 2 Post Evgeniyakpp Apr 27, 2017 3:29 pm

# 3 Post andogagra Apr 27, 2017 3:40 pm

# 4 Post Kraus Apr 27, 2017 3:55 pm

# 5 Post andogagra Apr 28, 2017 7:50 am

Good day! Thanks for the answers!
The question is: what is the training required for, if the automatic transmission control unit is the same? We replaced a couple of parts, but the block itself is unchanged (with the safety of all the data accumulated on this box). What does the box learn in this case? Or is it about checking the functionality of the unit and calibrating?

# 6 Post Kraus Apr 28, 2017 11:14 am

# 7 Post andogagra Sat Apr 29, 2017 6:13 am

What does the video and stuff have to do with it? I am here in order to clarify a number of important questions directly from specialists that interest me, and here they are. If you do not want to answer - do not answer, besides you there are others who can do it. The questions I ask are absolutely normal, tk. out of 10 services, 1 is normal, and the money is not small, so I have the right. And everyone considers themselves a pro! And how then to be? And do not confuse a forum and a company. Remind you what the forum is for? Greediness !? Do you feel the difference between 50 and 100? 100 and 200? If not, well then, apparently you are very lucky! And I count my money and should know that even if the price is really 100, they will do it correctly, and not through one place! And so I will ask questions, because there are those who answer, and the answers, like you, are only in the furnace, since you do not know how to communicate. And don't count other people's money.And I have already received the answers, thanks to those who do not behave like you. Learn to communicate, not turn a branch into a banter. Played.

# 8 Post arsas Sat Apr 29, 2017 8:16 am

On the ecu, you need to close two contacts through the resistance on the ignition on, the scanner does the same.
However, not every scanner can give the correct combination of numbers for the ECU to enter adaptation mode.
Adaptations have a limit.
You can compensate for the hole in the pipe with a patch until the hole is no more than 0.7 in diameter.

As for the money - well, when you buy belyash, you go to see how and where it was prepared?
Two Tajiks can cook in the basement, maybe a cook in a first-class cafe.
Belyash is one to taste, the price is different, feces too

But only after they replaced what was broken and the automatic transmission burns out again, normal hand-operated housekeepers change the valve body.
Returning to the whites - I bought a pie on the track, I don't buy it anymore.

# 9 Post arsas Sat Apr 29, 2017 8:23 am

# 10 Message Rav Sat Apr 29, 2017 8:50 am

# 11 Message andogagra Sat Apr 29, 2017 11:00 am

The answers have been received, but not in this thread, oddly enough (they advised, they say, good, correct guys), but here helluva lot of clever witches sit ala "aggregators". This is not for everyone, but for those who have especially distinguished themselves, on the forums of these comrades you can see right away, they are silenced with words, it is meaningless.

As a result, it turned out to be optimal both in terms of money and timing. The car will be handed over next week. The master dispelled some of the information, confirmed some, and chose the best option.

I wish everyone success with the 6T40 box, not a fun unit, but with proper operation, which also good specialists and craftsmen suggested, everything will be fine. Well, I wish a helluva lot of clever witches to be closer to the people, otherwise the stars and the crown interfere with correct reasoning and thinking.

The 6-speed automatic transmission GM 6T40 has been produced since 2006 at a Chinese plant and is installed on many models of the General Motors concern with engines of 1.6 - 2.5 liters. The transmission is considered the most massive in the lineup, according to the number of cars on which it is installed.

The 6T family also includes automatic transmissions: 6T30, 6T45, 6T50, 6T70 and 6T75.

For example, a 2010 Chevrolet Epica with a 2.0 liter engine:

Similar transmissions from other manufacturers:

Most often, automatic transmission data is sent for repair after the break of the wave spring

Debris from it falls into different parts of the box, causing serious damage.

Vibration is the second most popular problem due to the rapid wear of the bushings.

Also, you often have to clean or change the valve body due to contamination of the lubricant.

An additional radiator helps to avoid regular transmission overheating

All texts were written by me, have authorship of Google, are included in the original texts of Yandex and are notarized. For any borrowing, we immediately write an official letter on letterhead in support of search engines, your hosting and domain registrar.

Then we file a lawsuit. Don't try your luck, we have more than thirty successful internet projects and already a dozen court cases won.

In no case should you perceive as something insignificant the small jerks that have begun to accompany gear changes in automatic "six-speed", which are equipped with many Opel, Ford and Chevrolet. In fact, jerks indicate a problem with the control pressure, and if you do not pay attention to them, the malfunction progresses, which does not bode well in terms of money investment, which will subsequently be required for repairs.

Automatic transmissions, according to the number of gears provided in them, called "six-speed" by us, are representatives of a whole family that appeared in 2007, but according to a long-term tradition, General Motors is referred to as Hydra-Matic. The family now includes models 6T30, 6T40, 6T45 and 6T50. The numerical index in the designation represents the class according to the magnitude of the transmitted torque. The weakest in terms of torque is 6T30 - it is designed for engines with a volume of 1.4-1.8 liters.6T50 must "digest" the torque developed by engines over 3.0 liters.

As you can see, the displacement coverage is decent. GM has plenty of cars with engines of this size. In addition to Opel, which so far mainly introduced Belarusians to these automatic transmissions, they are installed on many Chevrolet models, as well as on Daewoo Gentra and a number of Buick and Saturn models. This alone makes the automatic transmission of the family potential candidates for becoming one of the regular customers of service stations who are engaged in repairing transmissions, however, Hydra-Matic has two creators.

The automatic transmissions in question were developed by GM together with Ford, which is why they have been installed since 2008 not only on various Fords with 1.6-3.5 liter engines, but also on Mazda Tribute and some Mercury models. Ford will label them as 6F. In particular, the most widely used 6T40, 6T45 and 6F35 are similar in design and interchangeable in terms of the main spare parts, although they have a number of differences due, for example, to the layout considerations in the engine compartment of the models of different brands on which they were installed. However, this is not the only difference between the GM and Ford variants. Some of them affected the operational problems of the 6T and 6F.

How did the automatic transmissions under consideration manage to "distinguish themselves", because not so much time has passed since the start of their production, which is why their operating time in most cases is relatively small and rarely significantly exceeds 200 thousand km?

At first, on 6T40, and then on 6T30, there were non-isolated cases of a breakdown of the outer circlip from the drum of the 4th-6th gears with subsequent damage to the drum.

Less often, but also there were breakages of the elastic disk, which supported the package in the same drum. It is noteworthy that nothing similar was observed on the 6F35. The lesson went for the future - an analysis of the programs downloaded into the "brains" of each of the boxes was made, from which it turned out that the GM programmers overdid it in the settings, making the automatic transmission work with high dynamic efficiency. At Ford, the settings were more forgiving, which provided protection from overly active drivers. After GM made the right conclusions and tweaked its software, the problem lost its original severity.

However, further operation and running time showed that 6T40 and 6F35 are poorly protected not only from overloads, but also from wear conditions, like most modern automatic transmissions of other models and brands. Unlike old automatic gearboxes, where the torque converter lockup was engaged in higher gears, in 6T40 and 6F35 it works with controlled slippage almost from the very beginning of the car's movement. In this mode, the blocking clutch is not completely pressed against the body, but with a microscopic gap, it slips and wears out rather quickly. Therefore, surprises can be expected from GT 6T40 and 6F35 after 120-150 thousand km.

But the main thing is that wear products contaminate the oil. Clutch packs of planetary mechanisms, gears, valves and other rubbing parts also contribute to this matter. First of all, the solenoids of the electronic-hydraulic control unit suffer from dirt. Meanwhile, the boxes under consideration have an adaptive self-tuning function that compensates for the influence of component wear on the timing of gear changes so that it runs smoothly. At the same time, the pressure control system is used for adaptation, as a result of which the ECU is able to adjust the gear shift parameters, maintaining them within the factory settings, as long as the solenoids work correctly. The appearance of jerking instead of a smooth gear change indicates a delay in shifting, and therefore, the beginning of problems with the solenoids.

Paradoxically, the Ford variant turned out to be less susceptible to this problem as well. It's unclear how this went unnoticed by GM, but regardless of its gearbox development partner, Ford has fitted the 6F35 with a dirtier oil filter.However, since it is already clear that 6F35 is also not insured against malfunctions caused by pollution, even if they start later than in 6T40, for her the recommendation to change the oil and filter at least after 70-80 thousand km is no less relevant. What's bad - the filter cannot be changed without disassembling the box.

The main consequence of a malfunction of the solenoids is not twitching, but insufficient pressure in the hydraulic circuits. As a result, the discs begin to slip in the clutch packs.

The presence of discoloration spots indicates local overheating of the discs in these places, and it could not be caused by something other than slipping, despite the fact that there are no obvious traces of mechanical wear on the clutch discs yet. They will appear, but later, but when the signs of wear become obvious, it will really be too late to hope that troubleshooting will cost "little blood".

There is another consequence of slipping - overheating of the oil, which is also a coolant for the automatic transmission. It also does not pass without leaving a trace, causing damage to the rubber seals. That is why it is impossible to ignore the small jerks that began to accompany gear changes in 6T40 and 6F35.

It was noted 6T40 and breakdowns, which are difficult to find an explanation. An example is shown in the photo. Nearby for comparison is a new shaft.

True, on the fragment of the shank there are traces of the sliding bearing bush sticking to the shaft. It is possible that the shaft wedged in the bushing bearing, and this, again, could be the result of low oil pressure. As a result, at some point, the shaft could not withstand a sharp increase in load.

The boxes of the family also have a potential pitfall - the gear chain of the output shaft drive. So far, the chain has not presented any unpleasant surprises, but we can expect that it will in the future, since it is known that such chains tend to stretch due to wear at the joints of the links. When the total wear reaches its limit value, the chain will begin to jump over the teeth. But the question of when this can happen in Hydra-Matic is still open.

Despite the fact that due to the above-described nuances 6T40 and 6F35 can hardly be called hardy, they are still quite reliable. In any case, their predecessor, the GM 4T40, was hardly better. And among the "automatic machines" with the number of gears of more than five other brands, there are many of those to which more claims are made. It is important to avoid active driving, bearing in mind that GM's initial software miscalculation indicated that certain gearbox assemblies did not have a large margin of safety. It is equally important to change the oil periodically, despite the fact that the Hydra-Matic is declared maintenance-free.

Sergey BOYARSKIKH
Photo by the author and from open sources
ABW.BY

We are grateful to STO "River Vine" for advice and assistance in organizing photography

18 thousand rubles! The difference in cost is tangible, it's worth considering! The question arises - these parts are really interchangeable and you can put an analogue of GM. It's a shame that the car warranty ended 2 months ago.
Thanks in advance for your help and advice.

yes, it is analog, but I would double-check.

Added after 20 minutes:

I corresponded with a master who repairs various automatic transmissions. Here's what he replied:
1. Is it worth it to change the oil without changing the filter (if you need to disassemble the entire automatic transmission to replace the filter)?
Master: “This automatic transmission is pouring in with terrible force, an artifact of GM with a bunch of sores, one hydraulic block with solenoids and an ECU is worth a lot. Therefore, if I were you, I would not even think about replacing ATF ”;

2. Data on Opel Astra or other brands with the same automatic transmission?
Master: “The cars are new, the transmission is modern, and a whole line has been produced for different engines, and complaints about the operation of the automatic transmission arise. Officials usually have only one answer, no mistakes, go in a known direction far out of sight ”;
3. And what do you think is the reason: poor quality of workmanship by the Chinese?
Master: “Low quality of workmanship, a number of operations in the manufacture of parts are skipped, low quality of material”;
4. The teammates changed the hydraulic block with solenoids, but what happens to the ECU?
Master: “The firmware flies, starts to shove when switching”;
5. Maybe some of the problems are just due to the fact that they do not change the liquid, tk. the regulations do not provide for such a replacement at all (of course, so that it breaks down faster)?
Master: “Dexron - VI, synthetic base, lives for a very long time, the problem is in the quality of the automatic transmission parts, the hydraulic block was probably specially made so that it would quickly collapse and kill the entire automatic transmission afterwards”;

6. For most astravods who are interested in the state, the liquid is already dark by 30 thousand km..
Master: “If the automatic transmission starts to shove when switching or slip, the fluid quickly darkens, its replacement will not help, the problem is in the hydraulic block of the automatic transmission in the first place. Again, the problem is in the heat load of the transmission itself, it often overheats ”;
7. “The trend of the modern car industry: the more modern the automatic transmission, the less reliable and less maintainable it is (it is a little more expensive to buy a new one than to repair it with high quality)”;
8. Is VW's DSG less problematic than the 6T40, or is it just rubbish?
Master: "A DSG box from VW - if you take a new car, then it's okay, in which case the dealer's brains out under warranty, after 3 years get rid of it."

I corresponded with a master who repairs various automatic transmissions. Here's what he replied:
1. Is it worth it to change the oil without changing the filter (if you need to disassemble the entire automatic transmission to replace the filter)?
Master: “This automatic transmission is pouring in with terrible force, an artifact of GM with a bunch of sores, one hydraulic block with solenoids and an ECU is worth a lot. Therefore, if I were you, I would not even think about replacing ATF ”;

2. Data on Opel Astra or other brands with the same automatic transmission?
Master: “The cars are new, the transmission is modern, and a whole line has been produced for different engines, and complaints about the operation of the automatic transmission arise. Officials usually have only one answer, no mistakes, go in a known direction far out of sight ”;
3. And what do you think is the reason: poor quality of workmanship by the Chinese?
Master: “Low quality of workmanship, a number of operations in the manufacture of parts are skipped, low quality of material”;
4. The teammates changed the hydraulic block with solenoids, but what happens to the ECU?
Master: “The firmware flies, starts to shove when switching”;
5. Maybe some of the problems are just due to the fact that they do not change the liquid, tk. the regulations do not provide for such a replacement at all (of course, so that it breaks down faster)?
Master: “Dexron - VI, synthetic base, lives for a very long time, the problem is in the quality of the automatic transmission parts, the hydraulic block was probably specially made so that it would quickly collapse and kill the entire automatic transmission afterwards”;

6. For most astravods who are interested in the state, the liquid is already dark by 30 thousand km..
Master: “If the automatic transmission starts to shove when switching or slip, the fluid quickly darkens, its replacement will not help, the problem is in the hydraulic block of the automatic transmission in the first place. Again, the problem is in the heat load of the transmission itself, it often overheats ”;
7. “The trend of the modern car industry: the more modern the automatic transmission, the less reliable and less maintainable it is (it is a little more expensive to buy a new one than to repair it with high quality)”;
8. Is VW's DSG less problematic than the 6T40, or is it just rubbish?
Master: "A DSG box from VW - if you take a new car, then it's okay, in which case the dealer's brains out under warranty, after 3 years get rid of it."

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An automatic transmission is an expensive component. There is no point in delaying the repair if it starts to work incorrectly. In a car service, such repairs are expensive. You have to pay for the work of specialists and for the details. Having studied the market and the price range of services in this segment, motorists come to the conclusion that repairing automatic transmissions with their own hands is not such a pointless undertaking. The prices of the workshop masters cannot be called modest, and the professionalism does not always correspond to the price. And, after some thought, motorists can decide to fix the problem on their own.

Wherever you decide to repair the gearbox, the whole process goes according to the following scheme:

• diagnostics,
• dismantling the box,
• disassembly of the box,
• complete set with spare parts,
• assembly (installation),
• installation on a car,
• diagnostics after repair.

To fix the problem yourself, you will need some car mechanic skills, tools, time to work, patience, and perseverance.

All automatic transmissions are arranged the same, but there are two types of transmission control - hydraulic and electronic. Their renovation has some differences.

It is important to notice transmission problems at the earliest possible stage. Then, with the correct diagnosis, complex repairs can be avoided. Quiet and smooth operation of the automatic transmission is considered normal. There are a lot of signs that something is wrong with the box. Most often these are extraneous sounds when changing gears or during robotic transmission. It can be crunching, clicks. An unpleasant smell also speaks of problems. It can appear during long-term or short-term operation of the box. It is worse if the gear shifting slows down, or one of them does not work at all. Then immediate intervention is required.

Do not be lazy to look under the car, it should be clean there. Red spots will indicate an oil leak from the transmission. Checking the oil level regularly is a must. Normally, it should be translucent, reddish in color. No burning smells or muddy shades! If they appear, it's time to change the oil.

Automatic transmission malfunctions often arise due to improper operation. The transmission becomes unusable due to insufficient oil level or overheating. For this reason, the gears wear out, the machine can jerk when changing gears. As a result, any part of the automatic transmission may fail. Shocks while driving indicate overheating of the oil and the appearance of problems in the valve body.

Aggressive driving with hard acceleration and braking will erase details. Does not add durability to the box and driving in traffic jams, slipping. All this leads to overheating of the box and has a bad effect on its general condition.

All faults are divided into two subgroups. They can occur in

• electronic control system,
• mechanical and hydraulic parts of the gearbox.

If a malfunction occurs, the automatic transmission goes into emergency mode, that is, it goes into third speed and does not switch. The corresponding icon appears on the display.

If problems have arisen with the electronics, then it will not be possible to fix them by repairing the automatic transmission. Therefore, it is important to understand the nature of the faults.

In diagnostics, the main thing is to collect the necessary information and interpret it correctly. Therefore, it is better to consult a specialist. Determine what the problem is at the service station, and take care of the repair yourself. Without proper experience and equipment, you will spend a lot of time on diagnostics. There are mechanical and computer diagnostics.

General scheme of diagnostic procedures:

• check the oil,
• check the operation of the engine at idle speed, the connection points of the wiring and cables,
• determine the error codes of the operation of the control units (CU) of the gearbox and engine,
• check the box on a car without movement,
• check the automatic transmission in motion,
• check the pressure inside the control system.

If the cause of the malfunctions is electronics problems, then most likely you will not need to dismantle and disassemble the automatic transmission. Diagnostics of malfunctions in this system is carried out by the control unit. It monitors the sensor signals, the transmission ratio and the resistance of the output circuits. Malfunctions of such parts and assemblies may occur:

• input sensors,
• electronic control unit,
• executive devices of the control system,
• violation of the integrity of the electrical wiring connections.

The transmission computer receives signals from various sensors. If some parameters are out of order, it writes the code of this problem (DTC) into memory. You can decrypt such numbers using a special scanner.

These are the main problems of the automatic transmission itself. They are conventionally divided into three subgroups:

1. Damage to friction groups, bushings and housings, calipers, planetary gear sets, pump and other mechanics.
2. Defective transformer. This includes:
   • breaks in the splines of the wires,
   • mechanical destruction of the blades,
   • overrunning clutch,
   • wear of the main blocking clutch,
   • depressurization of the piston oil seal.
   • Problems with the mechanics of the hydraulic plate.

If the diagnostics were successful and you cannot do without dismantling, then we proceed to this stage of the automatic transmission repair.

You will need a special lift, or at least a viewing hole. As well as a transmission jack and a set of keys. It is better to perform this procedure in a specially equipped garage or box. It will not be superfluous to invite several physically strong guys to help you move the removed box. Its weight is beyond the strength of even a very strong person. Further action plan:

1. disconnect all communication tubes and cables;
2. unscrew the torque converter mounting bolts, as well as the motor flywheel membranes;
3. remove and move the gearbox;
4. assess the scale of the breakdown and start repairing.

Before removing the gearbox, the oil does not need to be drained from it. However, then do not forget to substitute the container at the place where the oil supply pipes are attached when you disconnect them - otherwise you will get an ugly puddle under your feet.

All actions must be careful. Sudden movements can damage the splines on the input shaft of the diaphragm.

It is better to do automatic transmission repair with your own hands, having it at hand proprietary manual and a printed diagram of the gearbox. First you need to inspect all the systems that serve the gearbox, mounts and blocks. Then we proceed to the repair. For this:

1. We disassemble the gearbox, wash and dry the parts and check them for defects.
2. We change all gaskets, seals, as well as worn out parts.
3. Remove the inhibitor block and sump. We clean out the dirt inside. It looks like metal magnetic shavings.
4. We remove the wiring of the ring from the plug and push them inside the plug.
5. Remove the valve body, loosen the brake band bolts. We wash the valve body.
6. We check the clutches, gears and planetary gears for wear. We will replace it if there is such a need. All internal rubber bands must be changed!
7. We open the oil pump. We check all the details, especially the filter. We change what has already served its term. We use the manual so as not to swap parts.
8. We take out the valves and springs. We wash the valves. Their sticking can be the reason for incorrect operation of the automatic transmission. Replace the accumulator springs if they are broken.
9. Putting everything back into place. It is important not to confuse anything!
10. We replace rings and friction bolts.
11. We check the gear shift assembly and the large piston and put the oil pump in place.

Assembly takes place upside-down.

There are some points that it is advisable to take into account when repairing. Often a transmission problem is related to the filter. It will not be possible to change it without removing the valve body. And when it is removed, the gasket breaks. To replace it, you will need to disassemble the valve body completely. The same applies to the accumulator spring from first to second gear. A special stopper does not allow you to remove it without disassembling the valve body.All valve body gaskets are very similar, do not mix them up. Assembling the valve body, we tighten it with a torque wrench. It is important not to overtighten here.

If all the breakdowns are eliminated, we install the automatic transmission. The moment is responsible, haste is inappropriate here. During these works, the following recommendations should be adhered to:

• When installing the automatic transmission in its place, the diaphragm is checked for end runout using an indicator head. If such a defect occurs, then it must be replaced.
• The radiator is flushed until the gasoline is clean. Then a liter of transmission oil is poured into the gas turbine engine and put on the input shaft. You need to achieve a secure connection and a complete fit. Then you need to dock the engine with the box along the guide centering pins. The crankcases must abut completely.
• Tightening the bolts in the box is the next step. After that, the absence of gaps along the entire plane is checked. After connecting all the highways, the correctness of the connections is checked.
• At the final stage, oil is poured and the operation of the automatic transmission is checked at low engine speeds.

Beginning the installation of the box, be sure to check for the presence of centering pins on the crankcase flange - there should be two of them. If at least one is missing, the automatic transmission cannot be attached.

Automatic transmission repair and diagnostics do it yourself - not an easy but feasible task. Choosing a car with an automatic transmission, novice motorists believe that repairing it at home is impossible. This is not true. But before deciding to carry out such important work at home, you need to weigh all your possibilities. Then you will not be in for unpleasant surprises during the renovation.