4R55E Overhaul Kit 1994-1996

The 4R55E had one of the shortest careers of any Ford automatic. It went in behind the 4.0L Cologne V6 in Rangers, Mazda B4000s and Explorers for the mid-1990s and was replaced by the five-speed 5R55E for 1997, which means good used units are scarce and a rebuild is often the only practical way to keep one of these trucks on the road. If your 4.0L 4x4 slips when it is hot, shudders at highway speed, drops out of fourth, or takes its time finding reverse, this overhaul kit is the 4x4 version with everything that wears: a Transtec seal and gasket set, BorgWarner frictions and steel plates, the intermediate, overdrive and reverse bands, a filter, and the pump and extension housing bushings.

What the overhaul kit does in a 4R55E

The 4R55E is the heavy-duty sibling of the 4R44E. Both came from the A4LD and share its layout, but the 4R55E got stronger drive components for the 4.0L and a rating of about 550 lb-ft after converter multiplication. Every apply circuit, from the forward and direct clutches to the three band servos, runs on oil pressure that the computer sets through the EPC solenoid. The overhaul kit restores the rubber seals and gaskets that keep that pressure where it belongs, and replaces the friction elements that take the heat of a heavy V6 truck.

Symptoms this overhaul addresses

• Slipping in third or fourth under load, worst when towing or climbing
• Shudder or high slip when the converter clutch applies; Sonnax lists codes 628 and 741 for excess TCC slip
• No reverse, or a slow, soft reverse engagement
• Loss of fourth gear or no engine braking
• Leaks at the pan, front pump seal or 4x4 tailshaft
• Dark, burnt fluid with clutch and band material on the magnet

Separate the hard-part failure from the hydraulic one

Several 4R55E complaints look like worn clutches but start in the valve body. Sonnax points out that high TCC slip is often low apply pressure, and that the stator shaft seal should be updated and the converter checked before blaming the regulator. Their no-reverse tip is just as useful: unless the SSA solenoid is on, the direct clutch will not apply until EPC rises to about 20 psi, so a slow reverse can be a solenoid or EPC issue as easily as a burnt pack. End plug leakage in the valve body can cause no reverse or loss of third or fourth, and a worn coast clutch shift valve bore takes away fourth. Check the fluid against our ATF color and smell chart and test pressure using the harsh and delayed shift walkthrough. Clean fluid with a pressure fault points to the valve body; burnt fluid and debris mean it is time for this kit.

Fitment

This is the four-wheel-drive 4R55E kit. Four-wheel-drive units use a different tailshaft housing to meet the transfer case, so the extension housing bushing and rear seal are for the 4x4 case. The listing says 1994-1996, but the 4R55E did not exist before the 1995 model year; Wikipedia places it in 1995 and Sonnax dates the 4.0L version to 1996, and a 1994 truck will almost always have the A4LD. Check the case tag before you order, and remember that a 1997 4.0L truck has the five-speed 5R55E. If you want frictions, steels and seals without bands or bushings, see the 1995-1996 4R55E frictions and seals kit. Send us your year and VIN if you are not sure, and browse the rest of the family on our 4R55E and 5R55 parts page.

Install notes

• Soak frictions and bands in fresh fluid for about thirty minutes and use assembly gel on every sealing ring.
• Inspect the direct drum and its sleeve closely; Sonnax ties no-reverse cases to cracks there and at the center support. A replacement 4R55E direct clutch drum is far cheaper than a second teardown.
• Install the new pump bushing only after checking the pump gears and pocket for scoring, fit the new front seal with care, and update the stator shaft seal while the pump is apart.
• Replace the converter if the old unit failed with debris in the fluid, then flush the cooler and lines as shown in our cooler flush guide.
• Fill with the Ford MERCON-type ATF your owner guide specifies, check the level hot, and watch TCC slip on a scanner during the first road test.

Does this kit fit a 1996 Explorer 4.0L 4x4?

Yes, if the transmission is the four-speed 4R55E. Read the case tag or the transmission code on the door label. The five-speed 5R55E replaced it for 1997.

My 4R55E shudders when the converter locks. Will an overhaul fix it?

It can, but check first. Sonnax says high TCC slip is often low apply pressure, and recommends updating the stator shaft seal and checking the converter. A new seal set fixes the seal side; a worn converter or valve body bore needs its own repair.

What is included?

A Transtec seal and gasket set, BorgWarner frictions and steel plates, the intermediate, overdrive and reverse bands, a filter, the pump bushing and the extension housing bushing.

Will it work in a 2WD Ranger 4.0L?

This is the 4x4 version with the rear bushing and seal for the 4x4 tailshaft housing. Send us the year and VIN for a 2WD truck and we will match the correct kit.

Is a 1994 truck a 4R55E?

Almost never. The 4R55E arrived for the 1995 model year at the earliest, and 1994 trucks normally have the A4LD. Check the tag before ordering.

• ATF Color and Smell Diagnosis Chart
• 5R55 Harsh or Delayed Shifts: A Diagnostic Walkthrough
• How to Flush a Transmission Cooler After a Failure
• Checking Transmission Line Pressure