Two pairs of axial force transmitting coupling members (22, 24) and one pair of torque transmitting coupling members (26, 28) are arranged inside a housing (20). An annular cavity (42) each is formed in the housing (20) between each of the two pairs of axial force transmitting coupling members 922, 24) and the pair of torque transmitting coupling members (26, 28). A lubricant inlet opening (44) adapted to be closed opens into one of the annular cavities (42). An air outlet opening (54) is provided at the housing (20) at least approximately diametrically opposite the lubricant inlet opening (44) and communicates with the other of the two annular cavities (42) and likewise can be closed. In this manner the cavities (42) can be filled with liquid lubricant and freed of entrapped air in full measure in a short time.