5R55S Overhaul Kit 2002-2010, new and ready to install. Fits the 5R55S. Ships fast from the USA.
If your 2002-2010 Explorer, Mountaineer, Aviator, Lincoln LS, Thunderbird or Mustang V6 has a 5R55S that is weeping fluid, slipping once it warms up, or slow to pick up Drive on a cold morning, and the unit is coming out for a teardown, this is the gasket and seal set you need for the job. It is the Precision International KP53900S overhaul kit, listed for both the 5R55S and the 5R55W from 2002 through 2010. An overhaul kit is the soft sealing package: the pan and case gaskets, the piston and lip seals, the sealing rings on the shafts, and the O-rings that keep every clutch and servo circuit holding pressure. Clutch plates, steels, bands and the filter are bought separately.
The 5R55S has no mechanical shift valves of the old kind doing the thinking. As Transmission Digest describes, the solenoid body carries four on/off shift solenoids, a PWM converter clutch solenoid and three variable force solenoids that set clutch and servo apply pressure. Every one of those pressures has to travel through a sealing ring, a piston seal or a gasket before it does any work. When rubber hardens with heat and age, oil bleeds past, apply pressure drops, and the adaptive strategy in the PCM keeps adding pressure until it runs out of correction. That is why a tired 5R55S often feels fine for months and then starts slipping all at once. Fresh seals restore the sealed circuits the controls were calibrated around.
Not every 5R55S slip is a seal problem. Sonnax documents that worn overdrive and intermediate servo pin bores in the case leak apply oil and cross-feed release oil, and new seals will not cure that; the case needs sleeving. Worn VFS modulator bores in the valve body can also drop clutch pressure enough to set ratio codes. Work through our 5R55 harsh or delayed shifts walkthrough and the servo pin bore wear guide first, so the money goes to the right repair. If you are pricing the whole job, the 5R55S rebuild cost guide breaks down where the money goes.
The KP53900S is listed for 5R55S and 5R55W transmissions from 2002 to 2010. Per Sonnax, the Lincoln LS and Thunderbird ran the older 5R55N through 2002 and moved to the S for 2003, while Explorers and Mountaineers used the W for 2002-03 before the S took over. The N shares few parts with the W/S, so a 2002 LS or Thunderbird needs to be identified before ordering. The N case has two cast bosses behind the intermediate servo cover; the W/S has one. Check the transmission code on the door-jamb label, or send us your year and VIN and we will confirm it. Every other part we carry for this family is on our 5R55 parts page.
| Fits | 5R55S 2002-2010 |
| Part type | Overhaul Kit |
| Condition | New |
| Brand | OEM |
| Reference | KP53900S |
| Ships | From the USA |
| Warranty | 1-year |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
No. The KP53900S is an overhaul kit, meaning the gasket and seal set. Frictions, steels, bands and the filter are separate. If the clutches are burnt, add a master rebuild kit.
Yes, the kit is listed for both the 5R55S and the 5R55W from 2002 to 2010. It is not listed for the 5R55N or the older 5R55E.
Possibly not. Most 2002 LS and Thunderbird models used the 5R55N, which this kit does not cover. Confirm the transmission code on the door-jamb label, or send us the VIN and we will check it for you.
Mercon V. Fill through the T30 Torx fill plug and set the level hot. Plan on roughly 11 to 13 quarts from dry depending on engine, and add more if you also flush the cooler and converter.
Yes. The PCM has learned pressures that made up for the leaks. Clear the adaptive values with a scan tool and drive through all gears gently so it relearns around the new seals.
