Ford/Lincoln/Mercury 5R55S/5R55N/5R55W Transmission Pump Flow Control Valve Kit 56200-03K The OE flow control valve is designed to increase pump efficiency by rerouting excess line pressure back to the suction side of the pump. It is common for the plunger valve to become stuck open, or for the canister to wear. This decreases line pressures and results in delayed engagements. The Sonnax pump flow control valve assembly eliminates the sticking and wear problems with redesigned and precisely machined parts. Harder canister material resists wear and has improved valve support to prevent sticking. Plunger valve is made from case-hardened steel and has annular grooves to prevent side loading. Larger O-ring eliminates pressure loss at the pump face. Canister restores the regulated line orifice to improve valve and hydraulic stability. Drop-in-place replacement assembly for easy installation.