An axle driving apparatus comprising a housing being defined by two separable elements joined together along a parting plane; the housing rotatably supporting a pair of axle shafts, each of the axle shafts having a longitudinal axis; the parting plane of the housing being parallel to the longitudinal axes of the axle shafts; and a hydrostatic transmission disposed in the housing and including a pump, a motor, and a member having pump and motor mounting surfaces thereon.