Rear gear / Diff.

The rear gear or differential is a mechanical assembly that distributes power from the driveshaft to the rear wheels. It allows the wheels to rotate at different speeds during turns, preventing drivetrain binding. In rear‑wheel‑drive or all‑wheel‑drive vehicles, the differential also manages torque distribution between the left and right wheels, enhancing traction and handling under varying road conditions for optimal performance.

Located between the rear axle and the driveshaft, the differential consists of a set of gears, a housing, and a bearing system that maintain alignment. Proper lubrication and periodic inspection are essential; wear of gear teeth or failure of the bearing can lead to excessive heat, noise, and loss of traction. A malfunctioning differential may cause uneven wheel speeds, leading to handling instability and accelerated tire wear.