US Patent 6957531 Center section for a hydrostatic transaxle

A center section for a hydraulic pump and motor mounted in a transaxle casing. The center section has a protuberance formed thereon, a pair of flat surfaces separate from the protuberance and at least one fastener opening formed in the center section for receiving a fastener engaged to the casing. The protuberance is adapted to mate with a center section locator formed in the casing to establish an X-Y orientation for a central axis while the fastener provides a Z-axis locator for the center section.