A hydraulic pump housing comprises passages formed in an inner wall separating the gear cavity and the pump cavity to allow for the movement of fluid into and out of the gear cavity, thereby alleviating some of the power loss caused by churning lubricating oil. The hydraulic pump may comprise spaces integrally formed in axially opposing surfaces of the gear cavity walls adjacent the area where the gears mesh to enable the churning oil to expand and flow around the gears.
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