When a computer fails, it sends out different frequencies of sound. As a matter of fact, the car is the same. Let's learn about the basic breakdown of a car. First, tire noise and rear axle noise are distinguished from tire noise. The noise from rear axle is not the same. When the speed of the vehicle is below 48km/h, the noise of the rear axle will disappear, while the tire noise will continue to exist. When driving and sliding, the tire noise is the same, but the noise of the rear axle is different. Two. The resolution of the engine's abnormal sound and the rear axle noise will first drive a certain mileage on the flat pavement to make the working temperature of the rear axle to normal. Then, when the vehicle runs out of the abnormal sound, the speed is recorded, and the transmission is placed in the neutral position and then slowly added to the speed until the engine speed is different from the appearance of the engine. When the speed of the car is at the same time, it is observed that there is an unusual noise, which can be repeated several times to determine whether the noise is caused by the exhaust or the abnormal condition of the engine. Three, the resolution retarder bearing of the reducer conical active bearing and the differential bearing of the differential usually produces a piercing "brine" or "quack" sound, and the sound rhythm is stable and changes with the speed of the car. The front bearing of the conical driving gear of the reducer is larger when the vehicle is sliding, and the noise of the rear bearing is larger when driving. The noise of the differential bearing is usually a constant piercing sound, but its beat is much more relaxed than that of the conical drive gear bearing of the reducer. Four. The noise of the wheel hub bearing and the rear axle noise can distinguish the noise of the front wheel bearing when the car is driving and gliding. If the vehicle keeps the speed of the car, it can reduce the partial load, thus the noise can be reduced, and where the noise source comes from. When the speed is more than 48km/h, the rear wheel bearing noise is rarely heard unless the rear axle is seriously damaged, and the rear wheel bearing of the cracked rear wheel will produce "brine sound" while the back wheel bearing of the denuded rear wheel bearings emits "sand sand". Five. When the noise of the rear axle gear is resolved in the normal line, there is little relative motion between the differential gear and the planetary gear, so the noise can not be heard. In the course of vehicle driving, most of the reasons for the abnormal noise of the rear axle gear are caused by bad lubrication, which causes the gear gear to wear out the wound. If the abnormal noise can be heard at various sliding speeds, it is caused by the loosening of the screw cap of the reducer's drive gear. At low speeds, knocking occurs at the rear axle, causing a particularly dull noise when accelerating or decelerating. The above fault can be found from the following one or more reasons: 1. The gap between the axle shaft and the differential case of the differential is not proper. 2. Improper alignment of differential journal and differential case. 3. The backlash of the half shaft spline gear and the half shaft gear key slot of the differential is not proper. 4. The meshing gap of the differential half shaft gear and the planet gear is not proper. The gear gap of the active cone and the passive gear of the differential cone is not suitable. 6. The thrust washer is worn. The abnormal noise in the rear axle is due to improper gear engagement, improper adjustment of differential bearing load or both. When the abnormal noise is eliminated, the meshing clearance between the differential gear and the reducer gear, the pre load of the drive gear bearing of the decelerator and the contact trace of the gear of the reducer should be dismantled.