DRIVE SYSTEM FOR FOUR-WHEEL DRIVE VEHICLE

An on-demand four-wheel drive system includes a differential for the rear axle, a differential for the front axle, and a center differential connecting to the front and rear axle differentials. All three of the differentials contain a bidirectional overrunning roller clutch to enable locking of their respective outputs. The clutches provide a superior on-demand four-wheel drive system that distributes power to each drive wheel to propel the vehicle.