Abstract: A clutch actuator provides a mechanism by which a wheel may be selectively clutched to an axle for rotation therewith. In a preferred form, the actuator is employed in a wheelchair. An axle flange is fixed to each of a pair of rear axles, and an actuator is fixed to reach rear wheel hub for providing selective operative connection between each rear wheel and respective axle flange. Each actuator includes a housing having a detent. A coupling sleeve is axially movable within the housing and includes a bore registrable with the detent. A spring loaded plunger includes a cam disposed for axial movement within the coupling sleeve, and a ball carried within the bore is releasably retained in the detent by the cam of the plunger. The sleeve includes a transversely extending end disposed for engaging the axle flange for clutching the wheel.