Most buyers choose cars equipped with an automatic transmission. Most often this is caused by the desire to comfortably control gear shift modes without being distracted from the road. On average, automatic transmissions are designed for an operating period of at least 250 thousand kilometers. The problem - frequent slipping of the automatic transmission - can significantly shorten this period. To increase the reliability of the car and delay major automatic transmission repairs as much as possible, it is recommended to change the ATF oil more often and adhere to a measured driving style.
Features of towing a car with automatic transmission
In an automatic transmission, it is structurally impossible to achieve such work, since the torque converter, which transmits rotation from the engine shafts to the box, is switched off only when a speed of 60-80 kilometers per hour is reached (after which the motor turns the clutches of the box and, accordingly, the wheels directly).
Thus, it turns out that the automatic transmission will always work when towing a car . Considering this feature of the automatic transmission, it is important to approach towing a car with this gearbox with a competent approach and compliance with the basic rules of this operation
What if a car with a gun acts as a tug? Many will mistakenly answer that it is enough to connect two cars with a tow hitch and go. Such an approach is completely wrong and, like improper towing of a car with an automatic transmission, can also kill the transmission in a matter of kilometers. Remember, when using an automatic transmission as a tug, you need to use the gearbox modes correctly and not seriously overload it. We’ll talk about this and more in more detail later.
Torque converter and piston failure
The torque converter needs to be checked if the car does not move, there is no reverse speed, and a jolt is felt if it switches from “Parking” to “Neutral” mode. Also, you need to check the oil level in the box and the filter element.
If the piston is mechanically deformed, its debris gets into the transmission fuel and can damage the inside of the box. The result of this is difficulty in engaging reverse gear. The piston must be replaced with a similar component.
Automatic transmission malfunctions
All automatic transmission malfunctions can be divided into:
- problems in electronics;
- problems in hydraulic and mechanical systems.
So, in an electrical system, a controller may fail, short circuits may occur, control system sensors may break, and actuators may refuse to work.
Electronic failures are quite easy to recognize - the sensors instantly signal to the driver that the automatic transmission “does not get along” with the electrics. Moreover, emergency work programs are launched that maintain the functioning of the gearbox.
Malfunctions of hydraulic and mechanical systems are much broader:
- wear of clutch discs, brake bands;
- problems in the operation of the torque converter;
- malfunction of the oil pump, clogged channels;
- wear of shafts and gears;
- hydraulic unit failure.
Lack of gear oil
One of the signs of a faulty transmission is the presence of dark-colored oil. If the automatic transmission does not move back when hot, it is worth checking the oil with the engine running and warm.
If there is a lack of this fluid, extraneous noise will be noted from the box. The frequency of its replacement on an automatic machine is 40,000 / 60,000 km.
Thus, the automatic transmission requires constant care; the gear oil should be changed in a timely manner. Diagnostics of the box is necessary if the automatic transmission does not engage reverse gear. The problem is often associated with a lack of oil or a broken torque converter. The control unit can fail as a result of a voltage surge in the vehicle's on-board network or exposure to moisture on the board.
Cooling box
Heat in automatic transmissions is generated by both the friction discs and the torque converter; under heavy loads, overheating is extremely high; for this purpose, cars with automatic transmissions are equipped with a powerful cooling system. The radiator is built into the engine cooling radiator element, or is cooled using a separate air flow.
When slipping for a long time, the temperature of the lubricant of the automatic transmission rises sharply, until it boils. This leads to the destruction of the friction discs, which are forced to work “hard”. And in the worst case, it can lead to transmission failure.
Conclusion 1. It is permissible to slip with an automatic transmission, but not for long and intermittently.
Signs of automatic transmission slipping
The automatic transmission may not slip from day to day. At first, when the problem begins to develop, slipping of the automatic transmission is observed several times a day, repeating after three or four days.
The first signs begin with slow acceleration with the gas pedal pressed to the floor. The first step is to check the lubricant level. If it is not enough to the required level, then top it up. Fill only with high-quality and original oil.
If the slipping does not go away, then it is recommended to go to a service center to troubleshoot the automatic transmission.
A sharp increase in engine speed
The automatic transmission slips and increases engine speed, but the vehicle does not accelerate. This is the first sign of a box malfunction. For example, if the speed rises to 4000 rpm, the automatic transmission switches to Over Drive mode.
This indicates that the lubricating fluid has become unusable, or low-quality oil was poured, or the level is below the required level. The lubricant has lost its properties, does not reduce friction, as a result, gears do not shift, and the speed does not increase.
Long-term coasting
Automatic transmission malfunctions appear when the car continues to move when it should have stopped. For example, when a car owner takes his foot off the gas pedal, and the car continues to roll for some time.
Hot
When the automatic transmission slips when hot, the problem may lie in faulty solenoids. Symptoms: the driver cannot change gear, the speed may increase, but the speed, on the contrary, may drop.
The automatic transmission slips while driving when the solenoids fail. In order not to aggravate the situation, experts recommend immediately contacting service.
In the cold
When the automatic transmission is cold, it slips when starting. The tachometer will show high rpm, but the car will not be able to move, or it may start moving, but the speed will not increase. You can press the gas pedal all the way to the floor, but this will not increase the speed, although the car will roar and rush forward like a beast.
Read
Automatic transmission oil ATF SP3: analogues, characteristics and application
Slow downshifts
If the reverse gear of the automatic transmission is slipping, or slow downshifting is observed, this is also one of the symptoms of a malfunction of the automatic transmission. The driver feels it like a push.
When switching
When the automatic transmission slips when changing gears, there may be a malfunction in the electronic control unit. Errors in software, aging electronic brains all lead to the fact that the box will work intermittently.
The driver feels shifting failures as a push or jerk when changing from one gear to another. The car starts to jerk, sometimes it comes to a stop, and then starts moving. The latter occurs when the automatic transmission disease is completely advanced.
Sounds at high speeds
The driver hears dull knocks at high speeds - this means that the torque converter is faulty. If they appear intermittently, the machine may last for some time without repair. If it happens regularly, this will mean that the oil pump gears are worn out.
Often the sounds are accompanied by a hum, rattling of the entire box, and the automatic transmission slips. In this case, a check at the service center is required.
Problems engaging reverse gear
Problems with engaging reverse gear may also be due to the fact that there is a malfunction in the box. This problem especially manifests itself in the cold season.
Switching occurs with a slight stop, the box slips. The driver does not observe a smooth ride. Sometimes we will feel a push or a jerk.
Hydro problems
So, if you experience jerks when changing gears, then most likely this is due to the valve body. At first they may be barely noticeable, but then slowly but surely they will intensify. Pay attention to this and better not delay diagnostics and repairs.
Problems with the valve body can arise due to improper operation of the machine. This is primarily due to warming up, or rather the lack thereof. The automatic transmission, like the engine, definitely needs warming up, especially in winter. We wrote a separate article about how to warm up automatic gearboxes.
If there is a problem with the valve body, the car may jerk, and shocks and vibration may occur in the box. Sometimes the car may not move at all. As a rule, the on-board computer will alert you to such a problem.
In addition, the torque converter can be the cause of noise, vibration, rustling and other unpleasant sounds emanating from the box. And again, in this case you need to go to a car service center or call a tow truck. If you do not notice such symptoms, but when changing the transmission oil, you have a lot of chips in the pan, then there are obvious problems with the torque converter. Most likely, the car service specialists who will change your oil will inform you about this themselves. On average, repairing a torque converter is cheaper than repairing a valve body.
Causes of car slipping
Above we described the main reasons why a car with an automatic transmission slips, and now let's look at each of them in more detail.
Hydraulic unit
As mentioned above, valve body malfunctions can often cause a car with an automatic transmission to slip. Such malfunctions most often result from clogged channels of the valve body itself. With this problem, lubrication of the key elements of the automatic transmission is not ensured, and therefore slipping of the clutch is observed. With such a problem, as mentioned earlier, the solution is quite simple - cleaning these same channels or replacing the air filter of your car. The valve body can only be cleaned by a special service center that is equipped with all the necessary equipment. Also, recently this type of valve body cleaning has become popular, such as cleaning with special compounds or using ultrasound.
The modern auto repair industry, with completely new technologies in solving such problems, can almost completely eliminate clogged channels and avoid replacing the valve body. However, this is a rather labor-intensive procedure that occurs directly with the dismantling of the hydraulic unit itself and may take several days to complete.
Pump and solenoid block
If you contact a car service center with problems regarding the valve body, then you need to remember that after repairing the valve body, it is necessary to replace all the filter elements of your car, as well as change the oil itself directly in the gearbox.
This is due to the fact that solenoids quickly become unusable, especially if you use old or low-quality oil. Before replacing solenoids, the technician measures the pressure directly in the lubrication system. This procedure, which is simple for an experienced professional, allows you to detect certain problems with solenoids. If the pressure in the lubrication system is quite low (most often this is accompanied by your car slipping when hot), then this almost always indicates some kind of malfunction related directly to the solenoids or the pump.
If such a problem is detected, all failed elements are replaced directly, after which the performance of your transmission will again be at the highest level. It is also necessary to replace the solenoids with so-called solenoid packs
This precaution will significantly reduce the recurrence of this breakdown and extend the life of both the automatic transmission and the car itself.
Clutches
Also, after performing all the above steps, many auto repair services carry out diagnostics of clutches in order to completely eliminate the possibility of your car slipping. This is due to the fact that the clutches themselves are short-lived, wear out quite quickly and subsequently become completely unusable. Normal figures for friction clutch wear are considered to be 250–300 tkm. Most often, it is at this boundary that the friction clutches wear out, requiring their subsequent replacement. The work itself is very complex and time-consuming, which makes it impossible to do it at home.
Automatic transmission ECU (Electronic control unit)
The last of the possible causes of slipping in a car with an automatic transmission is considered to be incorrect operation of the transmission control unit. With this problem, a so-called malfunction of the ECU occurs, which leads to your car slipping. With this type of problem, the only possible solution may be to completely replace the electronic control unit itself. Diagnosing this problem is quite simple, but in most cases it is not possible to do it yourself. The cost of such work varies greatly, which is explained by differences in the cost of the cars themselves with automatic transmission. Despite the fact that the work itself of replacing the electronic control unit is quite simple, doing it at home is strictly unacceptable.
Thus, we have examined the main reasons why a car with an automatic transmission slips. Despite the apparent simplicity of the work to eliminate certain faults that caused the car to slip, it is highly not recommended to repair the car yourself. Otherwise, you risk completely ruining the car itself or spending a much larger amount on repairs.
If any automatic transmission malfunctions are detected, including slipping, it is recommended to immediately contact a proven, high-quality car repair service so that professionals can take care of your car.
Transmission Axle Seal: Common Leak Location
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An axle seal can cost you around $20.
If your mechanic checks the leak and he tells you it's just your axle seal, it could cost you a couple of hours of labor and you could be back on the road in a few hours if parts are readily available. Axle seal failures are common and the dealer usually has these seals in stock. But if it's your input shaft seal, plan to leave your car for a day or two and expect labor costs to be upwards of eight to ten hours.
How does automatic transmission slip occur?
Slippage can manifest itself either as slight slipping when driving a car, or as significant cranking of the engine while idling when switching to higher gears. There can be a lot of reasons for the transmission slipping. The most common and easily eliminated reason is the use of low-quality or old gear oil. In this case, the problem is solved by replacing the filter element and oil in the gearbox. However, this allows you to solve the problem only with minimal slipping of the box. If the problem worsens, a lengthy and labor-intensive repair of the gearbox is necessary. If your automatic transmission slips, for example when it’s cold, this indicates that the clutches are not working properly.
Hydraulic unit
In some cases, the cause of automatic transmission slipping is clogged valve body channels, which do not provide high-quality lubrication to the moving elements, which in turn leads to slipping of the clutches. In this case, automatic transmission slipping is eliminated by cleaning the valve body. The valve body channels are cleaned using special compounds or ultrasound. Modern technologies make it possible to effectively clean oil supply channels from scale and old oil. It should be remembered that this work is performed exclusively with the dismantling of the hydraulic unit and takes several days.
Pump and solenoid block
It is necessary to simultaneously change the filter elements and oil in the gearbox while cleaning the valve body. In most cases, when cleaning the valve body, the solenoids are replaced, which also become unusable from the use of old and low-quality oil. The pressure in the lubrication system is measured, which allows you to determine if there are problems with the solenoids. If the pressure is low and the automatic transmission slips when hot, there may be problems with the pump or solenoids. In this case, the failed elements are replaced, which allows the transmission to return to full functionality. If it is necessary to replace solenoids in an automatic transmission, we recommend performing this work with solenoid packs, which will ensure their correct and trouble-free operation for a long time.
Clutches
Simultaneously with assessing the condition of the valve body when the gearbox slips, the clutches are inspected. During operation, clutches can wear out and become unusable. As a rule, after a mileage of 250 - 300 thousand kilometers, the degree of wear is such that the gearbox clutches have to be replaced. This work presents significant difficulties, since it is necessary to remove the gearbox from the car and completely disassemble it. For this work, special equipment is used, which allows not only to correctly perform dismantling work, but also to assess the condition of the moving elements inside the automatic transmission.
Set of new friction discs for automatic transmission
Automatic transmission ECU (Electronic control unit)
In some cases, the cause of gearbox slipping may be improper operation of the transmission control unit. In this case, electronic brains send incorrect signals to mechanical moving elements, which leads to their slipping. In this case, the problem can be solved by replacing the control unit. Note that diagnosing such breakdowns is not difficult. If the control unit fails, this will be immediately displayed during computer diagnostics of the transmission. In this case, the cost of repair depends on the specific car and the specific transmission. It must be remembered that, despite the apparent simplicity of the work, due to the high cost of the failed control unit itself, the total cost of repairs will be quite significant.
Brief summary
So, if we find out that deviations in the behavior of the car are associated with slipping of the automatic transmission, you should immediately go to a trusted service station to diagnose your gearbox.
It is diagnostics that allows you to clarify the diagnosis and begin troubleshooting, knowing what exactly will have to be changed. Since the operation of the automatic transmission is controlled by its own electronic unit, diagnostics cannot be performed using standard means - you need to have the appropriate equipment and software.
Sometimes this procedure does not reveal problems, and after replacing the TM and oil filter, the operation of the transmission returns to normal. But if there are symptoms of gear wear, then in most cases you have to solve the problem by completely disassembling the unit. In particular, this cannot be avoided if the valve body is faulty or if the friction rings are faulty.
It is impossible to estimate the budget for repair work in advance, since everything depends on the specific malfunction, and several of them may be discovered during the repair of the box.
Automatic transmission slips: reasons
When the automatic transmission slips, you need to check the transmission oil
Pay attention to its level - it must correspond to the norm. If necessary, you need to change the oil or add it
Sometimes more serious problems arise:
- Destruction of friction clutches, which are coupling elements (slippage begins when the engine is cold).
- The solenoids have become unusable (this problem manifests itself “when hot”).
- The hydraulic system has failed (this is a consequence of contamination of the oil pump channels).
- Air filter malfunction (the problem appears when the engine starts).
Next, we will tell you what a driver needs to do when dealing with various symptoms of slipping.
Hot
If the oil is changed, but the problem with slipping remains and the automatic transmission slips when hot, this is evidence of a failure of the solenoid block. Solenoids deteriorate due to the use of low-quality working fluid. You will have to change the electromechanical valves, because the service life of the solenoids is less than the service life of the gearbox. Before replacing the solenoid valves, it is worth measuring the pressure in the transmission system - this will help identify the cause of gearbox failure.
At reduced pressure (this is when the fractional gears slip when “hot”), we can say that the problem lies in the solenoids or in the oil supply pump. After replacing the faulty components, the operation of the automatic transmission is completely restored.
Often in this case it is necessary to change the valves - it is better to do this with solenoid packages, since a single replacement may not produce results.
In the cold
If slipping occurs “when cold,” you need to check the friction discs installed on the planetary gearbox. Frictions work in a hard mode, so they wear out quite quickly. The nominal shelf life of friction clutches is 250,000 - 300,000 km. This is approximately the same as the entire automatic transmission, but the clutches can be destroyed long before the car covers the required distance.
When starting off
Slipping occurs when the gas pedal is pressed sharply. In this case, you can hear the sounds of rubbing elements that cannot “grab.” The clutch appears after slightly depressing the gas pedal. But if you do not release the gas, you can hear a strong blow in the area of the automatic transmission. Usually such problems appear in first gear.
A similar malfunction may not occur every time. For example, after leaving the garage there were extraneous sounds in the area of the automatic transmission, but during the second start of the engine there were no more sounds.
Using a special device, we determine the speed of the automatic transmission input shaft - if it corresponds to the speed of the engine crankshaft, the problem is slippage. A zero value indicates a faulty torque converter. One way or another, the automatic transmission needs to be repaired.
In all gears
When switching from one gear to any other, throttle shifting begins to occur. It's similar to pressing the clutch in a manual transmission without reducing the speed. The next gear then, of course, switches on, but only after a pause. If you press the gas pedal sharply, you can expect strong shocks. Slipping occurs precisely at the moment of switching gears - at other times the engine operates as usual.
This can occur due to severe overloads, when the normal speed limit is at least 150 km per hour. The oil burns quickly, and behind it the friction clutches themselves burn. Here there is a clear need to repair the gearbox with mandatory filter replacement.
When shifting from 2nd to 3rd gear
This problem can be solved by replacing the brake band. You will have to dismantle the side cover and check it for wear on the seals.
Faulty valve body as a cause of automatic transmission slipping
As mentioned above, often the cause of automatic transmission slipping is incorrect operation of the automatic transmission valve body. Malfunctions of this nature are caused by excessive clogging of the oil channels. This means that the working elements of the gearbox do not receive sufficient lubrication, resulting in the effect of clutch slipping. This problem is solved by cleaning the oil channels of the hydraulic plate, followed by replacing the lubricant and oil air filters of the vehicle.
Cleaning of the hydraulic unit is carried out in special service centers where the necessary equipment is installed. Among modern methods, services such as cleaning the automatic transmission valve body using special compounds, as well as ultrasound, are becoming increasingly popular. Using modern technologies used in the automotive repair industry, clogged channels are cleared, eliminating the need to replace an expensive valve body. The procedure often takes a long time to complete, with the labor-intensive process lasting several working days. Reason: to clean the oil lines of the vehicle’s hydraulic system, it is necessary to remove the hydraulic unit from the vehicle.
Friction disc replacement technology
If the car owner has sufficient experience in carrying out such operations, you can replace the clutches in the automatic transmission with your own hands in a garage. The room where the work will be carried out is thoroughly cleaned of any remaining dirt and dust accumulations. To successfully carry out repair and restoration work, an appropriate repair kit is selected that is suitable for a specific vehicle equipped with an automatic transmission:
- Friction disc set.
- Seals, seals, gaskets.
- Filter elements.
Sequence of work:
- removing transmission oil from automatic transmission;
- dismantling the box from the car;
- disassembling the gearbox;
- replacement of all elements included in the prepared repair kit;
- Assembling the automatic transmission, the steps are performed in the reverse order;
- installing an automatic transmission on a vehicle.
When not to skid
Do not try to skid on an automatic transmission if your car is one of the old monsters of the last century. Cars with high mileage suffer from severe wear of the torque converter. The transmission cooling radiator becomes clogged over time, which requires immediate replacement of the automatic transmission. If you are the owner of such a car and are not ready to give up your beloved friend, try not to go on long routes in heavy snow drifts.
If your car is “Japanese” or “European” of an old model, it may have a built-in air cooling system for the automatic transmission, while auxiliary external blades are installed on the surface of the torque converter, which circulate air to relieve the temperature. These automatic transmissions can only cool during movement, so slipping on them is contraindicated.
Conclusion 5. Modern car models from Japanese and European manufacturers with automatic transmissions do not suffer from this drawback; they will get you out of the snowdrifts without any problems.
For a true car enthusiast or an experienced professional, there are no insoluble problems on the roads. The main thing is to know your car like your own and listen to the advice of driving sages.
Is it possible to slip and rock a car with an automatic transmission if you are stuck in winter?
As you know, winter is a difficult time for every motorist. In such a case, not only does the load on the engine, gearbox and battery increase, but often we simply cannot get out of the snow rut, which leads to the need to push the car out or call a tow truck. With mechanics, operating a car in winter will be somewhat easier, since you can try to rock a stuck car. Is it possible to act in the same way with an automatic transmission, rocking the car, applying gas slightly? Let's talk in more detail about whether this is dangerous and whether it will lead to serious car malfunctions.
Basic modes
The first thing you should do is familiarize yourself with the operating modes of the automatic transmission, since you won’t be able to drive an automatic without these nuances. So, what are the designations of the letters on the automatic transmission and what gears do they represent?
- P – Parking
. This mode involves blocking the shaft and drive wheels. The relevance of use is observed if the driver leaves the car or during a long stop. Only after the vehicle has come to a complete stop can this mode be activated, otherwise the gearbox may be damaged. To activate another position from this mode, you must use the brake pedal. If the surface is relatively flat, there is no need to use the handbrake. On a steep slope, you must follow the procedure for applying and releasing the handbrake. To set it up, you need to pull the handbrake while holding the brake, then release it, and the car will move slightly. All that remains is to activate the “P” position. To release the handbrake, move the lever to driving mode and remove it from the handbrake while holding the brake. - N – Neutral gear
. It is relevant if it is necessary to move the car a short distance with the engine running, for example, in a car service. Some drivers believe that activating this mode while driving downhill will save fuel. In fact, this is not the case, since you will still have to switch to mode D, which is why the gearbox will undergo additional load. Also, driving with an automatic transmission does not require activation of the neutral position during short stops, for example, at a traffic light. - R – Reverse
. The mode must be activated if you need to move in reverse. It is permissible to switch to this mode only after pressing the brake pedal and stopping the car completely. Activating the mode in question while driving will lead to damage to engine elements, transmission and the gearbox itself (read our expert’s article on how to do it automatically). - D – Basic driving mode
. It is this mode that is often used to move forward. Movement is possible at any available vehicle speed from zero to maximum. - L – First gear only
. Used for off-road driving or other difficult road conditions. Switching to this mode is unacceptable if the car is moving at a speed above 15 km/h. - 2 – Only the first 2 gears
. Suitable for driving a vehicle on a winding mountain road. Another option is towing another car or trailer. Driving at speeds above 80 km/h is an obstacle to activating the mode in question.
