5R55W Sun Shell 2001, remanufactured and ready to install. Fits the 5R55W. Ships fast from the USA.
A clunk when you go from throttle to coast, a whine that follows road speed, or a teardown that shows chewed splines and a rough bearing in the sun gear shaft all point the same way on a 5R55W: the sun shell assembly has worn out. This is a remanufactured 5R55W sun shell for 2001-and-later builds, supplied as the shell with its ring gear and the forward sun gear already in place. The forward sun gear on this assembly has 55 teeth, and the shaft carries its own bearing, so you are getting the complete rotating assembly rather than a bare stamping you still have to build up.
Ford describes the 5R55W/S gear train as three compound planetary sets worked by three bands, three multi-plate clutches and two one-way clutches. The sun shell is one of the members that ties a clutch drum to a gearset: it carries the forward sun gear and the ring gear section shown in the photo, so every bit of torque that passes through that path loads its lugs, its splines and the bearing in the shaft. Because it is a rotating hard part rather than a friction element, it does not wear out from heat the way a clutch pack does. It wears from slack. Once the splines or the drive lugs open up, each change between drive and coast slams the parts against each other, and a worn shaft bearing lets the sun gear run out of center against the pinions it drives.
Parts in this family are not as interchangeable as they look. Sonnax warns that the earlier 5R55N shares only a few parts with the W and S, and a Transmission Digest TASC Force article notes that the W carries its own front planet and sun gear that were not carried into the S. Treat the tooth count as the deciding check: this shell is the 55-tooth forward sun gear version.
Most 5R55W clunk and slip complaints are hydraulic, not hard parts. Rule out the easy causes first: check fluid level the Ford way, scan for codes, and follow our 5R55W noise diagnosis guide to separate a gear-train noise from a pump, converter or driveline noise. If the unit is already out, inspect the old shell directly. Grab the sun gear and try to rock it inside the shell, look for shiny wear at the lug edges, and spin the shaft bearing by hand. Any clear free play or roughness means the assembly is done. If you are not sure whether your case is a W or an S, our 5R55S vs 5R55W guide walks through the identification points.
The listing is marked 2001-up for the 5R55W. In service, the W was built for 2002-2003 Ford Explorer and Mercury Mountaineer models before the 5R55S took over those trucks for 2004-2005, so in practice this is an Explorer and Mountaineer part. Hard parts changed inside that window, so count the teeth on your old forward sun gear (this one has 55), compare the lug pattern and the bearing in the shaft, or send us your year and VIN before ordering. It is not a 5R55E, 5R44E or Ranger part, and it should not be used to rebuild a 5R55N. Everything else for this family is on the 5R55 parts page.
| Fits | 5R55W 2001 |
| Part type | Sun Shell |
| Condition | Remanufactured |
| Brand | OEM |
| Ships | From the USA |
| Warranty | 1-year |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
This assembly has a 55-tooth forward sun gear with a bearing in the shaft. Count the teeth on your old sun gear before ordering; if the number is different, it is a different version and will not match.
It is listed for the 5R55W. The 5R55N shares only a few parts with the W and S, so do not use it in an N. Some W and S hard parts differ as well, so match the tooth count and lug pattern or send us your year and VIN to confirm.
Yes. It is the sun shell with the ring gear and the forward sun gear installed, with the bearing in the shaft. Thrust washers, bearings for other positions, seals and frictions are not included.
Mercon V. Sonnax points out that early factory Mercon V fill before May 2005 was linked to solenoid problems, so flush out the old fluid and cooler completely.
Yes. Ford 5R55 units built after 2002 run an adaptive shift strategy, so reset the adaptives with a scan tool and drive the vehicle through all gears so the PCM can relearn.
