Patent ID: 8028520

Claim:
A center section for use in a hydraulic drive device including a hydraulic pump cylinder block and a hydraulic motor cylinder block disposed within a common housing, the hydraulic pump cylinder block driven by a pump shaft and the hydraulic motor cylinder block driving a motor shaft, the center section comprising: a pump mounting surface on which the pump cylinder block is rotatably disposed and a motor mounting surface on which the motor cylinder block is rotatably disposed, wherein the motor mounting surface is perpendicular to the pump mounting surface; a motor shaft opening formed in the center section, into which at least a portion of the motor shaft extends; first and second fastener openings extending through the center section whereby fasteners may be extended to secure the center section to a portion of the housing, each fastener opening having an axis extending parallel to the motor shaft opening; wherein the pump mounting surface and the motor mounting surface are both located entirely between a first plane extending through the first fastener opening axis and perpendicular to the pump mounting surface and a second plane extending through the second fastener opening axis and perpendicular to the pump mounting surface; and hydraulic porting formed in the center section and comprising a first port passage extending from the pump mounting surface to the motor mounting surface and a second port passage extending from the pump mounting surface to the motor mounting surface, wherein a portion of the first port passage extends parallel to a line extending from the first fastener opening to the second fastener opening.