Abstract: A hydraulically operated planetary transmission and motor assembly mounted on the hub of two or more wheels of a four wheeled vehicle for providing wheel driving torque with the transmission set in drive. In an alternate form, the transmission and motor assembly is mounted on the hub of a winch to provide the power drive. The transmission is hydraulically engageable and disengageable and includes a lock whereby the transmission can be locked in either the engaged or disengaged position. The arrangement of components provides easy access for maintenance and for change out of gears to gear sets having different gear ratios all within the same transmission housing.