4R55E Shift Kit 1994-07, new and ready to install. Fits the 4R55E. Ships fast from the USA.
The 4R55E only lived a short life behind the 4.0L V6, roughly the 1995 to 1997 Explorer, Ranger and Mazda B4000, but plenty of them are still on the road and most share the same story: a slipping 2-3 shift, a burned overdrive or 2nd band, or a truck that suddenly will not move. This listing is the TransGo SK 44-55E valve body kit, the same kit TransGo builds for the whole 4R44E, 4R55E, 5R44E and 5R55E family, so the 1994-07 range reflects the kit's coverage rather than one truck. It goes in through the pan and does not require pulling the transmission.
The 4R55E shifts with solenoids that are all normally open. TransGo's sheet lists the four-speed pattern: first gear uses SS1, second uses SS1 and SS2, third uses none, fourth uses SS3, and reverse uses SS1. Those solenoids decide which gear is commanded; the valve body decides how hard each clutch and band is applied. TransGo found the stock calibration lets that apply pressure drop as low as 40 psi while line pressure is far higher, which is why a 4.0L working a trailer glazes its bands. Sonnax adds that the converter clutch regulator is fed from line pressure set by the EPC circuit, so a dirty EPC solenoid or a leaking EPC bore also weakens lockup.
The SK 44-55E raises forward and band apply pressure, firms lockup slightly, and reroutes the forward circuit so a stuck EPC solenoid no longer strands the truck. It includes a new aluminum end plug and three spring choices, an EPC limit valve that must go back in if your separator plate has a hole over that spot (Ford dropped it from later valve bodies), a tapered orifice for the 2nd band feed, high-temperature clutch rings and a center support shim.
If the truck always starts in third gear, it is in limp mode and the fault is electrical. TransGo lists the shift solenoids at 22 to 48 ohms, TCC at 9 to 16 and EPC at 3.1 to 5.7, and our guide to bench testing transmission solenoids shows how to check them. A worn SS2 can also cause a 2-3 flare, so rule it out. Then use our shift flare vs slip guide to tell a calibration problem from worn frictions. If the fluid is burned and full of debris, plan on a rebuild with the kit installed during it.
Listed for the 4R55E, 1994-07. In practice the 4R55E itself was built from about 1995 (Sonnax dates it to 1996 with the 4.0L) and was replaced by the 5R55E during the 1997 model year, but this kit also fits those later five-speeds, the 4R44E, and the 5R44E. A 1994 Ranger or Explorer automatic is almost always the older A4LD and needs a different kit. It does not fit the 5R55W, 5R55S or 5R55N. Check the transmission tag before you start, or send us your year and VIN. Related five-speed parts are in our 5R55 collection.
| Fits | 4R55E 1994-07 |
| Part type | Shift Kit |
| Condition | New |
| Brand | TransGo |
| Ships | From the USA |
| Warranty | 1-year |
The 4R55E was the heavier-duty version paired with the 4.0L V6, mainly in mid-1990s Explorer, Ranger and Mazda B4000 trucks. It was replaced by the five-speed 5R55E during 1997. The kit fits both.
Red is the standard choice for daily driving. Orange gives firmer shifts and a firmer 3-2 coast downshift, and orange with the yellow inner spring is the firmest. A truck that tows often is a good candidate for orange.
No. Starting in third is limp mode, which means the computer has shut off the solenoids because of an electrical fault. Fix the wiring, sensor or solenoid problem first; the kit fixes shift quality, not missing commands.
No. The kit modifies your existing valve body. Only replace the casting if the bores are badly worn, and even then a Sonnax Zip Kit can often repair the common EPC circuit wear.
Refill with MERCON V, check the level hot, clear codes, and drive through every gear over several trips so the computer adapts to the firmer apply.
