Four-wheel drive axleshaft clutch mechanism

A part-time four-wheel drive system for a motor vehicle includes a first set of wheels on a rear axleshaft driven from a transfer case through an axle differential, a front driveshaft driven from the transfer case, which transmits power to front axleshafts through a front axle differential. Integrally formed with the front differential mechanism is an automatic center disconnect which selectively connects and disconnects the front driveshaft from one of the front axleshafts. A cam mechanism within the differential mechanism moves a cam follower outward thereby producing a splined connection between the differential output and the selectively engaged front axleshaft so that the second wheel set is driven from the transfer case. When two-wheel drive operation is selected and the vehicle is driven in the opposite direction that which produced engagement, the differential casing rotates circular cams in the opposite direction causing the cam follower to move inboard, thereby disengaging the spline connection that produced four-wheel drive. The other front axleshaft is continuously connected to the differential mechanism and causes certain of its components to rotate in the opposite direction after the transfer case is disconnected from the front driveshaft.