Ford 5R55E Transmission Master Rebuild Kit 1997-Up

This is a master overhaul kit for the Ford 5R55E five-speed automatic and its four-speed siblings, the 4R44E and 4R55E, in 1997-and-up applications. That family sits behind the 2.3L and 2.5L four-cylinder and the 4.0L V6 in the Ranger, Explorer, Mountaineer, Aerostar and Mazda B-series, so it is the unit most independent shops see when a mid-size Ford truck comes in slipping. The kit is a master less-steels package: frictions, gaskets, rubber and Teflon sealing rings, lip seals, O-rings and the pan filter are in the box, and the steel reaction plates are not.

Less-steels is the normal way these get rebuilt. Pull your steels, check them on a flat surface for cone and heat discoloration, and if they are flat and not blued you reuse them. If a pack cooked, you buy the steels separately for that drum rather than paying for a full set you do not need. Measure clearance on every pack during assembly rather than assuming the kit stack matches what came out -- the 5R55E ran several friction thicknesses over its production life.

The failure this unit is known for is the servo bore. The intermediate and overdrive servo bores in the aluminum case wear oval, the servo piston seal loses its wipe, and apply pressure bleeds off. That shows up as a slipping or delayed 2-3 shift, a soft overdrive apply, and ratio codes in the P0731-P0736 range. A seal kit alone will not fix a bore that is already worn -- inspect both bores with the servos out, and if they are scored or stepped, sleeve the case before you put a fresh kit in it. Also inspect the coast clutch drum and the planetary thrust surfaces while it is apart, since debris from a failed pack usually took them with it.

Manufacturer part numbers on this kit are W56004L and RHT96-107. Confirm your case is a 1997-or-later unit before ordering; the earlier A4LD-based cores use different friction and seal geometry.