5R55E Shift Kit 1994-07

Rebuilding a 5R55E out of a 4.0L Ranger, Explorer or B4000, or a four-speed 4R55E from the mid-1990s, and want it to stay rebuilt? This is the new TransGo SK 44-55E, and it is at its best when the transmission is already on the bench. Along with the valve body recalibration that stops the hard-throttle 2-3 slip, the box carries the sealing parts TransGo uses to fix the center support and clutch ring leaks that send so many of these units back to the shop. This page focuses on those rebuild-time pieces and how to install them correctly.

Why a rebuilt 5R55E fails again without it

Fresh frictions and bands do not change the calibration that wore out the old ones. TransGo's instructions state that stock shift apply pressure for the clutches and bands can be as low as 40 psi even with higher line pressure, which is what burns forward clutches and the second and fourth bands. The kit's red forward control spring and aluminum end plug raise that pressure, the tapered orifice controls the second band feed, and the EPC limit and converter relief assembly protect the circuit. Put new soft parts in without these changes and the slip that burned the last set starts again on the first heavy pull.

The rebuild parts inside the box

• Upgraded early and late center support sealing rings
• A center support shim to correct end play
• New high-temperature clutch rings
• Four 1/4 inch plastic balls and a small rivet for the separator plate
• The valve body springs, plugs, orifice and drill bit for the recalibration

Symptoms of a center support or ring leak

• Slip or flare that gets worse as the fluid gets hot
• Forward clutch or band failure soon after a previous overhaul
• Hard-throttle 2-3 slip or a 2-3 cut-loose
• Ratio slip codes in the P0731 to P0735 range that TransGo lists for this kit

How to confirm before the teardown

If the unit is still in the truck, rule out the electrical side first. TransGo gives 22 to 48 ohms for the shift solenoids, 9 to 16 ohms for TCC and 3.1 to 5.7 ohms for EPC. Sonnax's vacuum test guide for the 4R44E, 4R55E, 5R44E and 5R55E ties 2-3 and 3-4 flares on the five-speeds to a worn boost valve, so a valve body that tests bad needs that bore checked during the rebuild. Our 5R55 shift diagnosis walkthrough puts these checks in a logical order.

Fitment

The listing title reads 1994-07, but TransGo's product page lists the SK 44-55E for all 4R44E, 4R55E, 5R44E and 5R55E from 1994 on, and the printed instructions name 1995-2010 builds in the 2.3, 3.0 and 4.0 V6 Aerostar, Explorer and Ranger and the Mazda B2300, B3000 and B4000. The Ranger Station shows the 5R55E in 1998-2011 4.0L Rangers. It does not fit the 5R55W, 5R55S or 5R55N. Center supports differ: the needle bearing type takes the scarf-cut hard plastic rings, not the rubber rings. If you are not sure what you have, send us the year and VIN, and browse the rest of the family on the 5R55 collection page.

Install notes for the rebuild

• Lubricate the rings and the support before placing rings in their grooves.
• Install the clutch rings so the ends just touch or leave a small gap. Pushed together firmly, they bind in the groove and will not seal.
• Install the shim, then the needle bearing, then the support and snap ring. Tip the case so the gear train weight pushes the support against the snap ring, then push on the drum through the support. A little movement is right; if it is tight, remove the shim. TransGo notes end play is critical to prevent dumping at the lube dam.
• Do the required .063 inch cross-drill and seat the tapered orifice in the second band feed hole.
• Torque the valve body bolts 72 to 92 inch-pounds from the center outward, adjust the bands, and fill with Mercon V.

For the rest of the rebuild, the 5R55E overhaul gasket and seal kit supplies the seals and gaskets, and a replacement 5R55E valve body is the option if the bores in yours are worn beyond the kit.

Does this kit include frictions, steels or bands?

No. It is a valve body recalibration kit with center support rings, a center support shim and high-temperature clutch rings. Frictions, bands and gaskets come in a separate overhaul or rebuild kit.

Which center support rings do I use?

On the needle bearing type center support, TransGo says to install the scarf-cut hard plastic rings, not the full-circle rubber rings. Lubricate them and the support first.

Will it fit a 2008-2011 Ranger even though the title says 1994-07?

Yes, if it has a 5R55E or 5R44E. TransGo lists the kit for every 4R44E, 4R55E, 5R44E and 5R55E from 1994 on. It does not fit the 5R55W or 5R55S.

Can I use it on a used valve body?

Yes, but inspect the bores first. Sonnax links worn boost valves to flares on these units, and a worn bore can still leak after the kit is installed.

What fluid goes in after the rebuild?

Mercon V. Flush the cooler, fill, and check the level and cooler flow once the transmission is warm.

• 5R55 Harsh or Delayed Shifts: A Diagnostic Walkthrough