5R55W Transmission Pump Assembly for Ford Explorer

This is the front pump assembly for the Ford 5R55 family five-speed rear-wheel-drive automatic: the 5R55W, the 5R55S, and the 5R55N, 2001 and up. It bolts to the front of the case behind the torque converter and is driven by the converter hub, so it is the part that makes every bit of line pressure the unit has. Applications cover the Explorer and Explorer Sport Trac, Mercury Mountaineer, Ranger, Mustang V6, and the Lincoln LS side of the 5R55N.

The failure this fixes is pressure loss. When the pump gears and the pump body wear, the clearances open up and the pump can no longer hold pressure at idle or when the fluid is hot. What the driver reports is delayed engagement into drive or reverse on a warm restart, soft or slipping shifts that get worse the longer the truck runs, converter shudder, and in a bad case a unit that will not move at all until the revs come up. A pressure gauge on the line tap tells you which side of it you are on before you pull anything.

On the bench, this goes on after the case is clean and the stator support splines have been checked. Inspect the converter hub for scoring before you reuse it, because a grooved hub is what killed the pump bushing in the first place and it will do it again. Anyone doing a full overhaul on a 5R55W or 5R55S should be replacing the pump as a matter of course rather than reusing a worn one behind fresh clutches. Pair it with the overhaul gasket and seal kit for the same unit so the pump body O-ring and front seal go in new.