What Causes Rear Axle Noise?

[DeAdelyn]

Rear axle noise is primarily caused by insufficient gear oil or decreased viscosity, swinging of the bevel driven gear, loose rivets, leading to inconsistent tooth side clearance and uneven meshing, which results in abnormal noise. The rear axle refers to the rear drive shaft component of a vehicle's power transmission system, consisting of two half-axles that allow for differential movement. Additionally, the rear axle serves as a device to support the wheels and connect the rear wheels. Detailed explanations of specific causes and corresponding solutions: Insufficient gear oil or decreased viscosity: If the issue is caused by this, it can be improved by changing the oil, ensuring adequate oil levels, switching from multi-grade oil to single-grade oil, or using oil with a higher viscosity grade. Noise due to gear tooth surface damage: Severe damage to the bevel gear tooth surface, excessive wear, or excessive clearance can cause a "humming" noise while driving, along with a metal friction sound that increases with speed. The noise noticeably weakens or disappears when coasting in neutral. If a sudden, intense, and rhythmic noise occurs while driving and disappears when coasting in neutral, it indicates severe tooth surface damage or broken teeth. In such cases, the gears should be repaired promptly or taken to a 4S shop for servicing. Noise caused by improper bearing clearance: If the bearing clearance is too small, there will be a uniform "humming" continuous sound. If the clearance is too large, there will be a chaotic "rattling" noise that increases with speed. High-speed noise accompanied by housing heat indicates excessive bearing preload adjustment. Noise during both acceleration and deceleration suggests bearing wear or excessive looseness. If rear axle noise is confirmed after inspection, it is recommended to visit a repair shop for handling.