What faults can occur in the rear axle?
3 Answers
The faults that can occur in the rear axle include overheating, oil leakage, and abnormal noises. Fault causes: Excessive small clearance in the passive gear meshing; Over-tight adjustment of the main and passive gear bearings; Insufficient rear axle gear oil level, or non-compliance with standards. Wear, damage, or aging of oil seals; Excessive wear of the shaft neck; Overfilling of lubricating oil; Blockage of the vent hole, causing poor circulation of oil gas and air inside the rear axle housing; Cracks or sand holes in the rear axle housing; Damage to the sealing gasket or loose bolts, damage to the gasket. Wear and looseness of gears or bearings; Presence of foreign objects inside the rear axle housing; Excessive clearance in bearings or gears; Loose fastening nuts or bolts; Damage to bearings or gears. Inspection and elimination: In case of overheating, first check whether the oil level of the lubricant meets the requirements and whether the oil quality is intact; then check whether the clearance adjustment of the rear axle gears or bearings is too small, and if so, readjust it. If the oil level is insufficient, add more; if the oil quality does not meet the standards, replace it. If it is found during vehicle use that the half-shaft oil seal is leaking for some reason, it should be inspected and eliminated in time. Otherwise, the oil quantity in the rear axle will gradually decrease. Excessive oil leakage will directly affect the normal lubrication of the rear axle and accelerate the premature damage of components. At the same time, oil leakage often enters the brake drum, reducing braking efficiency and affecting driving safety. When the rear axle leaks oil, first check whether the fastening bolts are loose, whether the sealing gasket is damaged, and whether the oil seal is damaged. If so, tighten or replace them; otherwise, check whether the vent hole is blocked or whether there are cracks in the rear axle. If none of the above is the problem, there may be sand holes in the rear axle housing. If the rear axle oil leakage is severe, the axle housing should be replaced. The abnormal noise of the rear axle is sometimes difficult to distinguish from that of the drive shaft, so careful listening is required, and if necessary, the rear wheels can be lifted for inspection. The abnormal noise of the rear axle is generally caused by excessive clearance between the main and driven gears, severe wear or damage to gears or bearings, or looseness in the keyways of the differential gears and half-shaft gears. When the vehicle is running, the abnormal noise of the rear axle caused by a sudden change in speed is generally due to excessive clearance in the meshing of the main and driven gears. When the speed is stable, this noise is generally not easy to hear; while the noise caused by gear or bearing damage changes with the speed, and the higher the speed, the louder the noise; the noise from the looseness of the splines of the differential gears and half-shaft gears is only obvious when the vehicle is turning, and disappears when driving straight. When driving the vehicle, these noise characteristics can be carefully checked and repaired in time to avoid greater losses.
As a seasoned driver with years of experience, I've seen my fair share of rear axle issues. The most common problem is bearing wear, which causes a humming noise while driving, especially noticeable during turns. If left unrepaired, it will only get worse over time. Oil seal deterioration leading to leaks is another major issue—once the lubricant runs out, the gears can grind and get damaged, resulting in costly repairs. Half-shaft fractures also occur frequently, often due to excessive jolting on rough roads or when hauling heavy loads. Differential gear damage is not uncommon either, causing uneven rotation that transmits vibrations throughout the vehicle, making the steering wheel shake. Preventive measures include regular maintenance, changing the lubricant every two years, and checking for loose oil seals or bearings. If you hear unusual noises or feel vibrations from the rear wheel area, don’t delay—get it checked at a repair shop immediately to avoid hefty expenses. Once, I ignored a minor issue, and it ended up requiring a full rear axle replacement.
As a DIY car enthusiast, I believe checking rear axle issues should start with the basics. For example, after parking, feel the rear axle housing with your hand - if it's hot, it might indicate insufficient lubrication or oil seal leakage causing overheating. Listening for sounds is also crucial: start the car in neutral, and any humming or clunking noises suggest bearing or gear failure. Additionally, check for oil stains on the ground, which means the oil seal needs replacement. For DIY inspection, check if the half-shafts are loose or bent, but remember to use a jack for safety. For complex issues like internal differential damage, I'd visit a professional shop. For prevention, maintaining adequate lubrication is vital, avoid overloading or frequent rough road driving to prevent premature bearing wear. Regular inspections can save much trouble.
