A hydrostatic module is disclosed, including a pair of shafts rotatably
supported by a frame. Two yokes are pivotally mounted on the frame, each
having complimentary surfaces to the other yoke and to the frame,
minimizing the space occupied by the yokes. Stop means are provided on
the yokes and on the frame to limit the pivotal movement of the yokes. A
hydrostatic power unit is carried by each yoke, each connected to one of
the shafts. A control system, having a single piece control housing
containing servo pistons, pivots the yokes. The servo pistons
independently determine the orientation of the yokes. A single piece
fluid control porting plate is secured to the control housing to route
hydraulic fluid to multiple locations within the control housing. A fluid
manifold serves as a main structural element, with intimate proximity
between the manifold and the control housing allowing simplified fluid
exchange therebetween.