Abstract: A disc brake assembly carried within a defferential housing immediately to the rear of a transmission housing. The brake assembly includes a casting mounted to the rear of the transmission housing and which supports a disc brake construction adapted to engage discs on the output shaft of the transmission. The casting also pivotally supports an actuating lever, the other end of the lever being provided with a cam follower surface. One end of a rod is rotatably journaled and supports a cam which engages the cam follower surface. The other end of the rod is provided with a modified spherical surface which passes through a cylindrical aperture in the differential housing so that the other end of the shaft projects outwardly therefrom. The parts are so made that they can be readily assembled.