5R55E Transmission Master Rebuild Kit with Steels

This is the full soft-parts and clutch pack overhaul for the Ford 4R44E, 4R55E, 5R44E and 5R55E automatics built from 1997 through 2003. Those are the units that sat behind the 2.3L and 2.5L four and the 3.0L and 4.0L V6 in the Ranger, Explorer, Mountaineer, Aerostar and Mazda B-series. ATP part number FM-43.

The kit covers the frictions, the steel plates, the pan gasket, both valve body separator gaskets, the pump and case O-rings, lip seals and sealing rings. The steels are the reason to pick this kit over a cheaper one. Plenty of master kits ship without them, which is fine if your plates come out clean, but when a unit comes in burnt the old steels are heat-glazed and coned and you are replacing them anyway. Components arrive vacuum packed to boards so the frictions stay flat in shipping.

Normal bench sequence: tear the unit down, wash and air-check the case, then soak the new frictions in ATF for at least twenty minutes before they go in. Set your clutch pack clearance against the new steels and shim from there rather than assuming the old stack height carries over.

While the case is apart, put a light on the intermediate servo bore. Wear in that bore is the usual cause of a 2-3 flare or slide on this family, and new frictions will not cover for it once the bore has gone oval, so sleeve or bush it while the unit is open and you have access.