What is one of the three main jobs of a differential in an automobile?

The primary function of a differential in an automobile is to allow different movement of the two axles. This is crucial when the vehicle turns, as the wheels on the outside of the turn need to travel a greater distance than those on the inside. The differential achieves this by enabling the wheels to rotate at different speeds while still being powered by a single drive shaft. This design prevents tire scrubbing, enhances handling, and contributes to overall vehicle stability during cornering.

The other roles, while important in the context of vehicle operation, do not describe the specific function of the differential. The differential is not responsible for controlling engine speed, providing power to the transmission, or directly reducing tire wear. Its main role revolves around the dynamics of wheel rotation and axle movement, making it essential for effective driving performance.