The variable volume and pressure compensated design simplifies circuit design, and reduces heat buildup and noise. Four pump control options permit the designer to choose the most efficient means to power his hydraulic equipment. Choices include the standard pressure compensator control, remote pressure control, load sensing control, and horsepower limiting control. Brass piston slippers pivot and rotate to equalize wear while a fluid passage through the slipper reduces loading and provides lubrication for the piston shoe and wear plate. Hardened swash plate and trunnion pins provide rugged support for the piston block and associated rotating group components. Efficiently designed porting reduces noise at all pressure and flow levels for quiet, efficient operation that eliminates the need for noise shrouds. The rugged, cast iron body is thicker at stress points which contributes to quiet operation.