Patent ID: 7077778

Claim:
A bull gear of a differential gear assembly, comprising: a ring gear for inputting torque from a transmission; a support member supporting a differential pinion and supported on an axle, the support member transmitting the torque from the ring gear to the axle through the differential pinion, wherein the ring gear and the support member are toothed to be coupled together so as to be relatively axially movable and not-relatively rotatable, the ring gear having a first surface perpendicular to the axle, and the support member having a second surface to be leveled with the first surface of the ring gear; and a retaining member abutting against the first and second surfaces so as to prevent the ring gear and the support member from relatively axial moving, wherein the retaining member is provided on a pinion shaft supporting a pinion for transmitting torque from the transmission to the ring gear.