Abstract: A mounting for the transmission of a track laying vehicle wherein the transmission is longitudinally installed and removed from a power-pack compartment in the hull of the vehicle. The mounting includes a pair of collars slidably disposed on bosses on opposite sides of the transmission case for movement between laterally inboard and outboard positions. As the transmission is pushed into the power-pack compartment, the collars are in the retracted positions. When the transmission achieves an installed position with the collars aligned on the sprocket axis of the hull, the collars are moved to the extended positions wherein an external bearing surface on each collar engages an internal cylindrical pilot surface on a web adapter rigidly attached to the adjacent hull wall. The transmission is supported at the sprocket axis through the collars.