It is because the parts are worn, deformed and damaged, which makes the cooperation between parts worse and produces vibration and noise. The wear, deformation, fracture, looseness and balance damage of all parts and components of the transmission system will lead to abnormal sound of the transmission system. It is a phenomenon of failure and a precursor of functional failure. According to its unique law, it should be eliminated soon. First, the fault phenomenon 1. When the engine is idling, there is a "sand" sound when stepping on the clutch pedal, and there is a "rustling" or "clicking" sound when the clutch is disengaged or engaged; When the pedal is relaxed, the abnormal sound disappears. 2. When the transmission is in neutral, there is rhythmic sound, that is, the first shaft and the intermediate shaft often make abnormal sounds, and sometimes there are sounds in different gears. 3. Abnormal noise of the universal joint transmission system, the higher the vehicle speed, the louder the noise, and the clearer the noise when it is out of gear; It will also ring at low speed, especially when sliding (such as the universal joint bearing is too tight); Or when the speed changes suddenly, there is a sudden crash; Some abnormal noises are accompanied by shaking, and the shaking is aggravated with the increase of vehicle speed. 4. The drive axle has abnormal noise when driving, but the abnormal noise disappears when shifting. Or there is abnormal noise when driving, and the abnormal noise does not disappear when shifting. Sometimes there is no abnormal noise when driving in a straight line, but there is abnormal noise when the vehicle turns; Some do not go uphill, some do not go downhill, and some have abnormal noise when going uphill and downhill.

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