Fault phenomenon: An Audi car has traveled a total of 654.38+0.5 million km, and gradually feels weak in acceleration. When the control lever of the automatic gear of the automobile is put in the D 4 gear and starts to accelerate, it obviously feels that the acceleration is weak, and there is no abnormal sound between the engine and the automatic gear.
When accelerating, observe the speedometer and engine tachometer on the car, and find that the engine tachometer is obviously fast, but the speedometer responds slowly; After the vehicle speed increases, the speedometer increases, but the engine tachometer is still obviously high; When the car enters high speed, the engine tachometer can correspond to the speedometer. Therefore, it is concluded that the clutch slips when the car shifts gears, especially when it accelerates at low speed.
Fault diagnosis: This Audi car is a German original electronic automatic transmission car. Check the electronic control part, and there is no fault code output. According to the driver's report, the car has traveled 654.38+0.5 million km. Just changed the automatic transmission oil once, only changed 3L. It is considered that the automatic transmission is too dirty and blocked by dirt, resulting in insufficient oil pressure for shift control. Specifically, it is possible that the automatic transmission oil filter screen is blocked or in a semi-blocked state; It is possible that the control oil circuit of the direct clutch or the No.2 one-way clutch is not smooth, resulting in weak acceleration and clutch slipping.
According to the judgment, carry out disassembly-free maintenance and thoroughly clean and flush the automatic transmission.
Troubleshooting: Connect the automatic transmission of this Audi car with the automatic transmission cleaning equipment. Add a bottle of power lion automatic transmission cleaner (#6440 1) from the oil filler hole of the automatic transmission, and carry out the transmission cleaning cycle according to the above method. Just after cleaning, I found that the circulating oil was dirty. Asked why the newly changed oil is still so dirty, he replied that the transmission of this car has never been cleaned since it was running. This oil change is the first time and it has not been cleaned. So I decided to flush the automatic transmission vigorously.
In order to thoroughly clean and flush the blockage in the oil circuit, this time, the driving wheel of the car is supported, the rear wheel is covered with triangular wood, and the throttle is increased in the D 4 gear of the transmission to make the driving wheel rotate. Then brake the foot to slow down the wheel speed, and then increase the throttle to accelerate the wheel rotation. In the process of cleaning, I feel that the oil flow in the cleaning pipeline is very fast and the circulating oil is very hot. This cycle lasted for 40 minutes. Replace the new transmission cylinder after cleaning, and see that the discharged waste oil is dirty until the new oil is finally discharged.
The road test was carried out again after the car was leveled, and it was found that the acceleration performance of each gear was good. When accelerating, the car rushes forward smoothly and there is pressure behind it.