Rearaxle

The rear axle refers to the axle assembly at the rear of a vehicle that transmits power to the rear wheels and supports the vehicle’s weight. In most rear-wheel-drive and many four-wheel-drive layouts, the rear axle comprises an axle housing, one or more axle shafts, a differential, and related bearings and seals. The differential splits torque between the left and right wheels and allows them to rotate at different speeds during cornering. The assembly is often lubricated with gear oil inside the housing, and the wheel hubs at the ends provide mounting points for the brakes and wheels.

Two common configurations are used: the solid (live) rear axle and the independent rear suspension (IRS). A solid rear axle uses a single rigid housing that spans the vehicle’s width; it is strong, simple, and cost-effective, but can transmit more road irregularities to the cabin and can limit suspension tuning. IRS designs use independent half-shafts and separate wheel assemblies, improving ride quality and handling at the expense of greater complexity and cost.

Drive characteristics are influenced by the final drive ratio, the presence of a locking differential, and the use of an electronically controlled differential in some vehicles. In four-wheel-drive and all-wheel-drive systems, the rear axle may be driven by the transfer mechanism and may be equipped with a differential lock for improved traction in low-grip conditions.

Maintenance typically focuses on lubrication and seals: periodic replacement of the differential oil, inspection of seals for leaks, and checking bearings for wear. Common failure signs include oil leaks, abnormal noises, or increased axle play.