Distinguishing between abnormal engine noise and rear a […]
Distinguishing between abnormal engine noise and rear axle abnormal noise
First, drive the car on a flat road for a certain mileage to raise the working temperature of the rear axle to normal. Then, when the car makes abnormal noises, record the speed. After stopping, put the transmission in the neutral position, and then slowly accelerate , Until the engine speed is equal to the vehicle speed when the abnormal noise occurs, observe whether there is abnormal noise, repeat it several times to determine whether the abnormal noise is caused by exhaust gas or abnormal engine conditions.
The discrimination between tire noise and rear axle noise
The tire noise changes with the road surface, but the rear axle noise does not. When the speed of the car is lower than 48km/h, the rear axle noise disappears, but the tire noise continues to exist. When the car is running and coasting, the tire noise is the same, but the rear axle noise is different.
The difference between wheel hub bearing abnormal noise and rear axle noise
When the car is running and coasting, the noise of the front wheel bearing remains the same. For example, keeping the vehicle speed constant and applying a slight brake can reduce part of the load on the wheel bearing, thereby reducing the noise and discovering where the noise source comes from.
When the vehicle speed is greater than 48km/h, unless the rear wheel axle is seriously damaged, the noise of the rear wheel bearing is generally seldom heard. When the car is sliding or in neutral gear, the cracked rear wheel bearing will produce a "rumbling" sound, which will cause erosion. The rear wheel bearing made a "rustling" sound.
The resolution of abnormal noise between the tapered active bearing of the reducer and the differential bearing
The bearings of the reducer usually produce a harsh "rumbling" or "crack" sound, with a stable sound beat that changes with the speed of the vehicle.
The sound of the front bearing of the conical driving gear of the reducer is louder when the car is sliding, and the noise of the rear bearing is louder when the car is running.
The noise of the differential bearing is usually a constant harshness, but its beat is much gentler than the noise of the conical driving gear bearing of the reducer.
The resolution of rear axle gear noise
When traveling in a normal straight line, there is almost no relative movement between the differential side gears and the planetary gears, so no noise can be heard.
When the car is running, the reason for the abnormal noise of the rear axle gear is mostly caused by poor lubrication, which causes the reducer gear to wear scars. If the abnormal noise can be heard at various sliding speeds, it means that it is caused by the reducer. The driving gear nut is loose.
When the speed is low, there is a knocking sound on the rear axle, and when accelerating or decelerating, it makes a particularly dull abnormal noise. The cause of the above failure can be found from one or more of the following:
① The gap between the differential axle gear journal and the differential housing is improper.
②Improper fit between the differential cross shaft journal and the differential housing.
③Improper backlash between the half shaft spline gear and the keyway of the differential half shaft gear.
④ The meshing backlash between the differential side gear and the planetary gear is improper.
⑤Improper meshing backlash of the cone driving and driven gears of the differential.
⑥The thrust washer is worn.
When the vehicle is running, the abnormal noise of the rear axle is caused by improper gear meshing clearance, improper adjustment of the differential bearing preload, or both. When removing abnormal noise, it is necessary to disassemble and check the meshing gap between the differential gear and the reducer gear, the preload of the bevel driving gear bearing of the reducer and the contact traces of the reducer gear.