US Patent 7178336 Pump

A hydraulic pump apparatus having an internal sump formed by a housing having an internal portion and an end cap secured to the housing. A rotatable cylinder block is located in the sump and driven by an input shaft extending into the housing. The pump apparatus also has a system of hydraulic porting in fluid communication with the cylinder block. The porting includes a pair of system ports located on a first side of the hydraulic pump apparatus, a fluid inlet on a second side of the hydraulic pump apparatus, opposite the first side, and a bypass valve positioned on the second side adjacent to the fluid inlet. A case drain may also be formed on a third side of the pump apparatus.