Variable pressure pump with hydraulic passage

A variable capacity pump, comprising:

• a pump casing including a pump chamber, an inlet and an outlet;
• a pump member movably positioned within the pump chamber, the pump member pumping a fluid from the inlet, through the pump chamber and to the outlet;
• a control ring being movable within the pump casing to alter the volumetric capacity of the pump;
• first and second control chambers at least partially defined by the pump casing and the control ring, the first control chamber operable to receive pressurized fluid to create a force urging the control ring toward a first position corresponding to a minimum volumetric capacity of the pump, the second control chamber operable to receive pressurized fluid to create a force urging the control ring toward a second position corresponding to a maximum volumetric capacity of the pump;
• and
• a return spring urging the control ring toward the second position, a force of the return spring acting against the force generated by the pressurized fluid within the first control chamber to establish a first equilibrium pressure, wherein the control ring connects and disconnects the second control chamber from a source of the pressurized fluid based on a position of the control ring, the return spring force acting with the force generated by the second control chamber and against the force generated by the first control chamber to establish a secondary equilibrium pressure when the second control chamber is connected to the source of pressurized fluid.