The advantage of an automatic over a manual
Despite the fact that an automatic transmission is much more expensive, complex in design and contains many components and mechanisms, it has a number of advantages over a manual transmission. The main feature of the automatic transmission is the ability to operate without the need to depress the clutch and manually change down or up gear. As a result, driving comfort is achieved, the driver is less distracted and has better attention to the road.
The automatic transmission also provides a smooth change of gears, the moment of switching is almost imperceptible to the driver. There are also disadvantages. The automatic transmission takes much longer to accelerate the car. But the developers managed to fix this by adding the function of manual upshift or forced downshift. But not everything is so smooth. Over time, driving such a car becomes different - the automatic transmission jerks the car when the gear is engaged. There are many reasons for this phenomenon.
The car jerks during acceleration: how to find the cause of the problem
Relatively recently I had such a problem. When accelerating, the engine began to stall. If you press the trigger harder, it seems to stop, then starts again. The day is fine, the day is fine. Some kind of mysticism. It was difficult to get started and the ride was uncomfortable. This post is dedicated to those who have encountered or may still encounter such a problem. I hope the information will be useful to you.
In general, I was tired of this disgrace, and I stopped at the service station. Naturally they told me: “Change the spark plugs and you will be happy.” However, any experienced driver would say just that: “Check the spark plugs.” But the fact is that I checked the spark plugs, they looked quite good: there was a little carbon deposit (cleaned), the output was minimal, they were not filled with oil. I think, okay, I’ll replace it, what can you do.
I replaced the candles and became the happiest person in the world. Couldn't be happier. Do you think this is the end? Of course not. 2 days passed and the problem returned.
I think, okay, let's look further. I went to the service station and they told me, “Change the spark plugs.” I say I changed it. They tell me: “I bought bad candles.” I was like, “I see, all the best.”
I think - “Maybe the injectors are clogged?” Damn, they are difficult to clean. I asked my neighbor and he said, “Have you looked at the candles?” I almost started to get hysterical.
I think, okay, since everyone has only candles on their minds, we’ll dig from this side. What comes after the candles? That's right, ignition coils, or a coil. I have 4 of them. I started the car and started turning it off one by one. If after disconnecting one of the coils the engine operation does not change, then its time has come. Surprisingly, the engine responded to all shutdowns.
I think, damn, there must be something wrong with the gas supply. I took a homemade pressure gauge from a neighbor (by the way, to measure air pressure), climbed under the hood, unscrewed the valve and measured the pressure in the fuel rail. It showed 3.8 atmospheres, which is the norm for my car, even taking into account the deviation due to the fact that the pressure gauge measures air pressure, not fuel. Missed again.
Back to the coils again. I think he can buy 1 coil and change it one by one: a day instead of the 1st, then instead of the 2nd, and so on. Sorry for the money. I'll dig further. I would have gone through the whole car, but I was lucky.
One night I was driving around the city, and the car started shaking more than usual. I was delighted. He started to slow down, then accelerated sharply, then braked again, then accelerated sharply again. I wanted to completely kill what was composting my brains. I managed. When I got out of the car, it was shaking convulsively. I crawled under the hood and the first thing I did was start pulling the coils. Hurray, comrades! After I turned off the third one, nothing changed in the engine's performance.
The clock showed 01:00, fatigue knocked me down, and I wanted to sleep. But I didn't go home. I went to a 24-hour auto store, bought a BOSCH coil there, and replaced it right in the parking lot. I drove home happy and satisfied. The next day I was afraid to drive, I thought that everything would come back. But that did not happen.
As experienced auto mechanics say: “A good knock will come out!” So mine came out.
Solenoids
This is an electromechanical type valve regulator. Its main purpose is to perceive electrical impulses from the ECU and control the channels of the hydraulic plate. At the command of the control unit, the solenoids open or close them. Such elements are used on both automatic and robotic boxes. Thanks to them, the oil flow in the system is controlled. The solenoids are located in the valve hydraulic plate and are installed in the valve body channel with a pressure plate. The main problems with it relate to the electrical part. The element is connected via a wiring plug to the transmission ECU. On many transmissions, this connector is damaged, which is why the automatic transmission jerks the car when the gear is engaged. During computer diagnostics, a communication error with the solenoid is displayed on the screen. This problem can only be solved by completely removing the automatic transmission. We also note that the service life of the solenoids is 100 thousand kilometers. If there is a knocking noise when shifting gears, pay attention to when they were last replaced.
Why does the automatic transmission jerk?
An automatic transmission consists of dozens of mechanisms that must work harmoniously so that gears shift smoothly and on time. There are several variations of automatic transmission, and each unit developer tries to make their own improvements to it. In this case, we can name typical malfunctions for all automatic transmissions:
Failure or incorrect operation of the torque converter;
- Mechanically worn gearbox parts;
- Broken adjustments, including the control drive;
- Cable souring;
- Problems with the electrical component;
- Incorrect operation of the electronic control unit;
- Wear of friction clutches.
However, many of the above faults can cause complete failure of the automatic transmission. If the car jerks when the automatic transmission is switched to an up or down gear, and jerks are noticeable when accelerating or decreasing speed, the range of problems can be significantly reduced. Most often, the machine jerks during operation due to the following malfunctions:
The car is not warmed up well, in which case the problem should disappear as the trip progresses;
- Lack or excess of transmission fluid (ATF);
- The transmission fluid is unsuitable for use (contaminated);
- Worn gearbox mounts;
- The chassis of the car is faulty and there are gaps in it.
Most often, problems in the gearbox arise precisely because of the inattention of drivers who do not monitor the level of transmission fluid. It is important that there is enough of it in the gearbox, but not excessive. If you put too much ATF into the transmission, it will begin to foam because the pump cannot handle the volume available. In a situation where there is not enough transmission fluid in the gearbox, the mechanical wear of its elements increases. This is especially dangerous when operating a car in a city, where traffic lights, traffic jams and other road users regularly force the engine to operate at low speeds, which is a stressful situation for the transmission.
Jerks when accelerating
One of the common problems that worries car owners is jolts when changing gears. When accelerating, the car starts to jerk. In this case, you need to check the oil level. If it is at the minimum level, resume it to medium or maximum. The pump may not be able to produce the required oil pressure.
If the automatic transmission jerks the car when you engage the gear, also check the locking of the “donut” (torque converter).
What to do if the reason is ATF
Often the reason why a car experiences a shock or a jolt during braking is that the ATF level does not correspond to that recommended for normal operation of the unit. It turns out that if the working fluid has an excess or deficiency, this can provoke foaming. Then the automatic transmission pump fails to pump a sufficient volume of oil to the parts in contact one with the other. Constant oil deficiency leads to wear of some parts. Their forced contact “dry” ends in an unwanted jerk of the car, leading to strange jolts, and even sharp impacts when one of the gears is engaged. This is doubly undesirable for a car when it operates for a significant period of time in urban conditions, where there are constant changes in speed due to traffic jams, irregular traffic on roads with traffic lights, etc. In such conditions, problems with the automatic transmission progress literally before our eyes.
The following logical algorithm suggests itself: having detected the automatic transmission twitching when switching, the first step should be to check the fluid level. It should definitely be brought back to normal by adding the required amount or, if there is excess, draining the excess. Then check the fluid for cleanliness. If signs of contamination are found, replace it. It will also be necessary to change the filter, remove deposits from the filter mesh, etc. We must not forget that the box certainly requires that it be warmed up at a low temperature before starting to move.
Shocks in winter
Such symptoms are not necessarily a symptom of a malfunction. In most cases, the automatic transmission jerks the car when the gear is engaged due to unheated oil. When you turn on the engine in winter, you need to thoroughly warm up not only the engine, but also the transmission. Experts recommend continuing to drive 3-5 minutes after starting. The oil in an automatic transmission is the working fluid. It is this that transmits torque from the engine to the wheels. As the temperature decreases, the oil changes its viscosity.
To return it to its normal value, move the gearbox selector several times to position P, R, N, D and back. When the oil warms up to operating temperatures, driving the automatic transmission will become pleasant - the gears will not jerk during acceleration.
When the box has nothing to do with it
It should be noted that the reason why a car suddenly starts to twitch strangely when starting to move, braking or accelerating for no reason at all is not always the automatic transmission. There are cases when this occurs due to the influence of low-quality fuel or interruptions in the ignition system. Since the car is one system unit, a malfunction in the operation of the engine or ignition automatically leads to deviations in the functioning of the automatic transmission. Then car diagnostics are also inevitable.
The driver should make it an ironclad rule to follow technical recommendations and preventive measures that will make it impossible or, in the extreme case, delay as long as possible a malfunction in the operation of the vehicle. This is, first of all, filling the engine with only the high-quality oil recommended by the manufacturer. In addition, strict adherence to the interval for replacing filters and fluid and, as already noted, warming up the automatic transmission when using the car at low temperatures are mandatory. Of course, you also need to operate your car carefully and from time to time have it undergo a full technical inspection, using the services of reputable service centers and good diagnosticians.
Vibration in reverse
If, during acceleration, the transmission changes gears normally, but when the selector is switched to “Reverse” mode, the gearbox vibrates, there are several reasons for this. The first is a malfunction of the control sensors in the box.
It is very difficult to solve this problem with your own hands. Repairing automatic transmissions is best left to professionals. Using computer equipment, errors will be read and, depending on the malfunction, sensors or other elements of the box will be replaced.
Features of automatic transmission operation
Comfort when driving a car equipped with is combined with the periodic appearance of certain problems associated with the complexity of the mechanism and its improper operation. Kicks when shifting gears occur much more often if the car is stored outside or in a cold garage, since in this case the contamination and content of solid particles in the oil increases significantly, which significantly reduces the life of the unit.
It is advisable to store a car with an automatic transmission in a warm garage, or, in extreme cases, warm it up well before driving, and do not touch the transmission during warming up, and do not put it in gear when parked in the cold.
To prevent kicks during switching, it is especially important to carry out automatic transmission maintenance on time, and if malfunctions or breakdowns occur, start solving the problem with diagnostics, and based on the results, deal with them.
About oil change
Most malfunctions are caused by improper operation of the transmission. In half of the cases, automatic transmissions are repaired due to untimely oil changes. And if in mechanical transmissions it is filled for the entire service life, then for automatic transmissions the regulation is 60 thousand kilometers. If the car is driven under load (for example, with a trailer), this period is reduced to 40 thousand. It is not uncommon for old oil to smell like burning; this is a very bad sign. The color of the liquid should not be black. Fresh oil has a red tint.
Also, during operation, the gearbox mechanism produces chips. It is caught by special magnets on the pallet. Often there are several of them.
When changing the oil, be sure to clean the pan along with the magnets. The presence of chips in the hydraulic unit is fraught with breakdowns and malfunctions in the form of twitching and vibrations. Driving on dirty, black oil threatens rapid wear of the hydraulic plate and other automatic transmission parts.
An automatic transmission is one of the most complex and reliable components of a car, but when the mileage goes beyond 150-200 thousand kilometers, any gearbox will need a full repair. Even with regular maintenance, the use of high-quality gear oil and its timely replacement. If the automatic transmission slips during acceleration, this may indicate many problems - both insignificant and very dangerous.
Reasons why the automatic transmission jerks during acceleration
The first thing you need to do is determine when exactly the problem occurs. This will help with further diagnosis. You can find out in detail how diagnostics and repairs are carried out on this website. Typically, jerks, jolts and slipping appear in the following situations:
- Changing the position of the selector.
- Changing gear when accelerating or braking.
There may be several reasons that lead to such problems. Below are the most common:
- Temperature too low. The problem will only be observed until the liquid in it reaches operating temperature. This is normal for any automatic transmission and does not indicate any malfunction. The only caveat is that you should not drive an unheated machine, since the oil has not yet reached the required viscosity and cannot provide effective lubrication of the moving components (accordingly, before warming up, wear will be higher than usual).
- Poor quality or heavily contaminated oil. Gradually, the viscosity of the transmission oil increases, and foreign particles accumulate in it. All this increases the load on the automatic transmission, and it becomes increasingly difficult for it to function as before.
- Insufficient oil volume in the gearbox. It is necessary to determine the reasons for the lack of oil, and then top up to the previous level (or completely replace the transmission oil in the system).
A less common problem is jerking and jerking of the so-called adaptive units. It is quite possible that in this case there is no need to worry about why the automatic transmission jerks when accelerating or braking. Adaptive systems are “tuned” to a specific driving style, and therefore, in the event of atypical driver actions (or if another person is driving the car), they cannot immediately adapt to new conditions.
Technical problems leading to transmission jerking
Unfortunately, an automatic transmission can jerk not only due to poor-quality oil, incorrect adaptive settings or other minor problems. Malfunctions can be more significant:
- Severe wear on solenoids.
- Incorrect adjustments in the control system.
- Damage to the hydraulic unit or torque converter.
- With high mileage - worn clutches.
- Electrical problems in automatic transmission.
One of the main signs indicating problems in an automatic transmission is the lack of smooth operation of the unit. Jerks can be detected during braking, during acceleration, when starting from a standstill, when changing from gear to gear. The jerking is more noticeable when the car is driving at low speeds. It is better to avoid serious problems than to deal with their consequences. On the page https://centrakpp.ru/uslugi/regulirovka-i-diagnostika-transmissii/ you can read about diagnostics and correct adjustment of automatic transmission.
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BMW 7 series › Logbook › Push/kick of the automatic transmission when braking. Change of oil. Flashing.
From the very first day after purchase, there was a slight push/kick in the automatic transmission during hard braking, when shifting from third or second gear to first, as if someone had slightly hit you from behind. There were no shocks when accelerating. First of all, they checked the oil level, color, and presence of chips. Everything was normal, only the pan gasket was slightly sweating. In the future, I constantly monitored the level. I read a bunch of information on this topic, it turned out that this is a very common problem on the E65, many have measured it and drive like this. Resetting the adaptation helped to reduce the shocks to a minimum for a couple of weeks; replacing the elastic cardan coupling also did nothing. The experts condemned mechatronics. So I went for 2 years. But I was confused by the connection of these tremors to the time of year. I noticed that in the fall and at the end of winter (in wet weather) the tremors are stronger, you can even say that at this time of year they were continuous kicks/blows, in the winter there were rare tremors, and in the summer, at a temperature of 25+ they completely disappeared. In connection with this, it was decided to completely change the oil in the box, including flushing. It took 15 liters of original ZF Lifeguardfluid 6
, + tray with filter, + adapter and connector. The result, the automatic transmission began to work smoother, the shifts were much softer, but the shocks remained... There was one more option, an acquaintance who used to work at the dealer said that BMW had an order regarding this problem, and therefore it was necessary to update the firmware in several blocks with new, corrected ones. I signed up to re-flash all the units in the car to the latest current versions. The process itself took 3-4 hours, the result is there - not a single shock anymore. The gearbox is unrecognizable; sometimes you can only sometimes feel the gear shift itself in the place where there was a push-kick-blow. As it turned out, all my units had firmware from the factory, dated 2004. After that, no one ever updated them. For example, those that are installed now, the latest current firmware for E65 from 2013, in which many software bugs have been eliminated. It seemed that the engine also began to run a little smoother. If someone is tormented by such jolts and kicks when braking, first try to reflash the blocks of the box, or better yet, all the blocks in the car, to the latest software.
Issue price: Oil at the current exchange rate: 1100 rub. per liter + tray, adapter, connector for 10 thousand, + work Reflashing all units in Moscow: 7-15 thousand.
