1. There is oil seepage from the gearbox housing or oil pan. One reason is due to the aging of the seals and poor sealing, and the seals need to be replaced;

        Gearbox oil mainly plays the role of lubrication, cleaning, cooling, rust prevention and sealing. If the gearbox is short of oil, the internal lubrication of the gearbox will be insufficient, and it will be scrapped after long-term dry grinding.

2. Slow or stuck in gear and shock

       Start the engine, idling, press the brake, and shift into gear. Normally, it takes 1-1.2 seconds to have a feeling of shifting into gear. Release the brake pedal. The vehicle will start slowly without stepping on the accelerator and gradually extract to 10 -20 km/h vehicle speed. If it is more than 2 seconds after entering the gear, it is a delay in entering the gear, and it needs to be repaired immediately.

       Gear-in impact, any automatic transmission has a certain degree of impact when entering gears. If there is no feeling at all, it means that there is an internal fault. But the impact is relatively large, it is necessary to check and clean the valve body

       The problem of stalling in the gear is more obvious when the car is cold. There are problems with the gearbox and other body systems that cause this problem.

3. In any gear, the car does not move and cannot be driven

       The car can run for a short time after a cold start, but not when it is warm. This situation is mostly caused by damage to the input shaft or reverse clutch, or damage to the D/R brake. There may also be a serious lack of oil in the automatic transmission;

The linkage or cable between the shift lever and the manual valve rocker arm is released, and the manual valve remains in neutral or park.

4. The impact of shifting is large, and the sense of frustration is obvious

       This fault may be caused by the fact that the transmission oil is too dirty and the valve body is stuck. The oil inlet filter is blocked; the main oil circuit leaks seriously; the oil pump is damaged.

5. Abnormal noise

1. The abnormal noise of the bearing is closely related to the speed. The higher the speed, the more screaming.

2. The differential or main drive gear has abnormal noise. This kind of abnormal noise generally appears at a speed of 50-70 kilometers. Because the meshing surfaces of the gears are different, the noise is generally obvious when refueling, and the sound of releasing the accelerator is significantly weakened.

3. Abnormal sound of hydraulic system such as oil pump. This kind of sound is closely related to the speed but has nothing to do with the speed of the vehicle. When the speed is high, the oil pump is blocked from sucking oil and causes screaming. It should be noted that the gearbox system works together with the engine, chassis and other parts, and many sounds are mixed together, so it is not easy to identify.

6. The oil temperature is too high and there is a peculiar smell

       The gearbox body works by hydraulic oil. When the oil temperature is too high, some combustion will occur and an odor will be emitted, indicating that some executive components in the gearbox body are not working properly and need to be detected.

7. Skip or not upshift

       Generally, automatic transmissions have specific shifting speeds and vehicle speeds. If it is found that the shifting time is suddenly too long or too short, it means that the transmission ratio of the gearbox is disproportionate, and at the same time, it will feel that the speed of the engine is too high, and the situation is even worse. The other is that the transmission does not shift gears, which requires checking the transmission.

8. The gearbox slips, the engine is idling, and the speed is not increased

       Including two situations of high speed during smooth driving and high speed during acceleration -

1. The speed is high in the stable process, which is easier to test. For example, a vehicle with an engine displacement of 2.0 can usually reach a speed of 100 kilometers at 2600 rpm. If it often takes 3000 rpm or more to reach 100 kilometers for a period of time, it is generally due to It is caused by the failure of the high-speed gear of the transmission or the failure of the lock-up clutch inside the shifter, and the transmission needs to be repaired immediately.

2. The speed is too high during the acceleration process. This fault test is a bit complicated, because during the acceleration process, the increase of the engine speed is closely related to the accelerator pedal. The vehicle can be accelerated to 2500 rpm, but the engine will be boosted to 5500-6000 rpm at full throttle. Such a huge contrast is due to the fuzzy logic of the electronic control system of the gearbox.

9. Gearbox slips, engine idling

       There are also two situations when the engine is idling -

1. The gearbox is suddenly lowered from a high gear to a low gear in a short period of time, resulting in the sudden idling of the engine of the vehicle. The problem may lie in the control system or the cooling system. There is no problem with the gearbox itself.

2. In the process of accelerating or shifting gears, there is a brief slippage and idling. Most of the problems lie in the clutch and other related links in the gearbox. The gearbox should be completely disassembled and overhauled.