Abstract: A multiple-function mechanical coupling having inner and outer races, the outer race having an internal surface with peripherally spaced pockets defining ramp surfaces, the inner race having an outer surface with peripherally spaced pockets defining ramps that are situated adjacent corresponding ramp surfaces of the outer race. The inner race surrounds a circular torque transfer shaft. The inner race is split to permit radial expansion of the effective diameter of the inner race. A hydrostatic pressure actuator exerts a tangentially directed force on the adjacent ends of the inner race. A plurality of clutch rollers is received in the recesses in the inner surface of the outer race and the outer surface of the inner race whereby the races are locked together and the inner race establishes frictional engagement of the torque delivery.