Abstract: The wheel and rotor drive key assembly (10) comprises a wheel (12) having a plurality of integral torque-transmitting drive lugs (22) which extend radially inwardly from an inner surface (20) of the wheel (12) and axially across the inner surface (20) from one end to the other of the lug (22). The lug (22) has a radially inner face (24) extending axially along the lug (22) and includes a radially outwardly extending contoured opening or recess (30) defining undercut portions (34) of the drive lug (22). A complementary-shaped retention member or nut (40) is disposed therein so that laterally extending side of retainer portions (42) of the retention nut (40) engage the undercut portions (34) of the drive lug (30) in order to retain radially the retention nut (40). The retention nut (40) includes a threaded portion (46) of an opening (44) which receives a retention screw (90) disposed within an opening ( 56) of a U-shaped rotor drive key or cap member (50).