What should I do if the automatic gearbox fails? Maintenance methods of common faults

Answer: this question includes two situations: high speed when driving smoothly and high speed when speeding up, which is relatively easy to test. For example, a vehicle with an engine displacement of 2.0L can reach 100 km at 2600 rpm. If it often takes more than 3000 revolutions to reach 100 km, this failure is usually due to high gearbox failure or internal locking of the button changer.

The speed is too high during acceleration, which is a bit complicated, because the increase of engine speed during acceleration is closely related to the accelerator pedal. For example, in a normal Passat, when the engine speed reaches 2500 rpm, the small throttle can accelerate the vehicle, but the large throttle will be raised to 5500-6000 rpm. Such a huge contrast is controlled by the fuzzy logic of the gearbox electronic control system, so this standard needs a certain professional level to complete.

2. The influence of late filing and dead fire filing.

Answer: The criteria for testing gear shifting are starting the engine, idling, braking and gear shifting. Under normal circumstances, if you feel a shift within 1- 1.2 seconds, and release the brake pedal, the vehicle will start slowly, and gradually increase the speed to 10-20km/h without stepping on the accelerator. This is the normal shift standard. If there is a strong impact when entering the gear, it should be noted that any automatic gearbox has a certain degree of impact when entering the gear. If there is no feeling at all, it means that there is an internal fault, but the influence is unacceptable, and the problems caused are very complicated, and there are many aspects besides the gearbox; The case of dead fire in gear is that the engine will die in gear. This problem is more obvious when the car is cold. This problem is caused by gearbox problems and other body systems.

3, the vehicle can't afford to run

Answer: the vehicle can't afford to run. This is a driver's driving experience. This is really not a technical term. Vehicles can't afford to run, including no high speed, that is, vehicles can't reach 100 km/h anyway. The speed of each speed segment is very slow, that is, the accelerator is pressed heavily, but the vehicle still accelerates slowly, with poor response and no sense of fluency. This situation also includes a slow increase in engine speed. That is to say, the engine speed can't come up, but the speed is fast but not fast, so this is a complicated problem. The normal detection standard is that the vehicle is started, the accelerator is properly stepped on, the engine speed rises steadily, and the vehicle accelerates, generally around 2500 rpm, and the vehicle speed is between 25 and 30 kilometers. When the automatic gearbox enters the first gear, the engine speed drops down appropriately and then rises gradually, and the vehicle speed is obviously accelerated. When the vehicle is 40 kilometers, the second shift is made. After the gearbox enters the third gear, the speed of the gearbox will be further accelerated, and it will enter the high gear of the gearbox at a speed of 60 kilometers. During the whole process, the engine will be lifted again after properly descending in the upshift process, and will not idle and slip. General engine displacement bit 2. 0, the engine speed can reach 100km/h at 2500-3000 rpm. If it is necessary to further increase the speed, it is necessary to simultaneously increase the engine speed. If the engine refueling is stuffy, it generally means that the engine needs overhaul. If the engine accelerates strongly, it means that the internal teeth of the gearbox are wrong, the clutch is burnt out, and the button changer is mechanically faulty.

4. Engine idling

A: Engine idling usually occurs in two situations. One is that when the vehicle is stationary, the engine suddenly idles and the speed slows down before returning to normal. This situation generally shows that the gearbox suddenly drops from high gear to low gear in a short time, and the problem may be in the control system or cooling system, and there is nothing wrong with the gearbox itself.

Secondly, there are short-term slippage and idling phenomena when accelerating or shifting gears. The intuitive feeling is that the latter is not as powerful as the former, but in fact it is just the opposite. Most of the problems of the latter are related to the clutch in the gearbox, and it takes much more time and cost to completely disassemble and maintain the gearbox.

5. The engine speed is high when driving.

A: This problem includes two situations: high speed when driving stably and high speed when speeding up.

In the steady process, the speed is high and easy to test. For example, the displacement of an engine is 2. 0, the speed can reach 100 km at 2600 rpm. If it often takes a period of time to reach 100 km at a speed of 3000 rpm or higher, it indicates that this fault exists. Generally, this kind of fault is caused by the failure of the high gear of the gearbox or the failure of the internal lock clutch of the button changer, and the gearbox needs to be repaired immediately.

The speed is too high during acceleration, which is a bit complicated, because the increase of engine speed during acceleration is closely related to the accelerator pedal. For example, in a normal Passat, when the engine speed reaches 2500 rpm, the small throttle can accelerate the vehicle, but the large throttle will be raised to 5500-6000 rpm. Such a huge contrast is controlled by the fuzzy logic of the gearbox electronic control system, so this standard needs a certain professional level to complete.