What is the differential in an automobile and its role?

The differential transfers power from the transmission/driveshaftto the wheels/axles. If the car is rear or front wheeldrive ithas one on that axle. If the vehicle is all wheel drive it usually has one in the center on the car to transfer power front/rear. Some differentials are open and some are limited slip. Limited slip units are usually used in performance cars to get as much traction as possible.