Fault phenomenon: when the engine is running, it has "swish, swish, swish" abnormal sound, and the vibration is too large when it changes speed. Troubleshooting: in order to confirm the symptoms of the failure, that is, starting the engine test, in the idle running state, the sound is very small, can not hear clearly, but in the idle running state switch to ON, instantly "swish, swish, swish" belt slipping sound. The slippage of air conditioning compressor belt is the cause of abnormal sound. The reason for slipping is the aging of the belt, the bad belt tension wheel and the bad adjustment of the tension wheel. Second, confirm that the vibration of the gearshift is too large. It will generate great vibration when shifting from N gear to R gear, D gear shift and gear shifting. Driving test, from 3 to 4 gear lifting gear and from 4 to 3 gear, the variable vibration is smaller, the 1 gear and the 2 gear rise and drop between the gear and the 2 and 3 gear. The reason why the variable speed vibration is too large is that the rubber couplings of the driving shaft are aged or broken, the automatic transmission operates on high oil pressure or the parts in the automatic transmission are bad. First of all, find out the cause of the variable speed vibration. Repeat the operation of the variable speed selector to confirm the variable speed vibration state. The test results, from the N shift to the D gear shift, the clutch of the moment to create a "goo sneer" sound, vibration after the "click" a sound, in the driver's seat can also be clearly confirmed. If this sound is generated by automatic transmission, it is very difficult to understand. Lift the car up immediately, use it to rotate the drive shaft, and you can hear the small click of the click. Remove the drive shaft and find that the rubber coupling will deform. According to the above results, the bad parts, namely the driving belt of the air conditioner compressor, the belt tension wheel and the Zhang Jin wheel regulator, are replaced together. The three parts have better replacement effect. Because of the abnormal sound produced by the variable speed, the rubber shaft coupling of the drive shaft is replaced. After the test is finished, the engine's abnormal sound is completely eliminated, and the vibration from the N gear to the running gear and the shifting gear are completely eliminated.