Abstract: A variable displacement hydraulic system includes a charge system having a substantially constant charge pressure, a reciprocating piston type pump having a drive chamber in communication with the charge system, and a control valve regulating the flow of fluid from the charge system to the inlet of the reciprocating piston type pump which is manually movable from a closed fluid blocking position through a first range in which it varies and controls the quantity of fluid flowing to the pump inlet and a second range in which it varies the control of pressure of fluid flowing to the pump inlet at flow rates greater than those obtainable in the first range.