Abstract: The device for disconnecting the wheels from a vehicle's optional drive is mounted inside the support of the axle shaft, and the wheel hub is splined onto the axle shaft. The universal joint is diametrically positioned in relation to the support of the axle shaft by a bearing. The universal joint has an internal splined section which corresponds to an internal splined section on the clutch disc for "engage" and "disengage" positions. A fluid responsive actuating device is provided including a movable member in the form of a diaphragm or a piston connected to the clutch disc for axially moving, in response to the pressure or pressure differential from a fluid source to effect the engagement and disengagement of the clutch disc splines in relation to the axle shaft and universal joint splines.