an axial bearing 33 is arranged the annular piston 26 is axially supported via the axial bearing 33 relative to a pressure plate 34 by axially displacing the annular piston 26 the pressure plate 34 is also displaced and axially loads the plate package 14 in this way torque is transmitted from the first coupling part 12 to the differential carrier 15 in the fully open condition of the hang on coupling 4 no torque at all is transmitted so that the first coupling part 12 including the hollow shaft 8 and the ring gear 7 are stationary whereas in the fully closed condition of the hang on coupling torque is transmitted from the ring gear 7 to the sideshafts 19 19 u2032 for supporting the axial forces which are generated during the actuation of the hang on coupling 4 there is provided an axial bearing 37 which is axially arranged between an abutment face of the housing 10 and a supporting face of the first coupling part 12 between the pressure plate 34 and the second coupling part 24 there is arranged a returning spring 35 which in the unactuated condition of the actuating unit 6 returns the pressure plate 34 i e it axially loads same towards the hydraulic chamber 30 in the present embodiment the returning spring is provided in the form.