4R55E Planetary, new other (see details) and ready to install. Fits the 4R55E. Ships fast from the USA.
The 4R55E only lived a few model years, mostly behind the 4.0L Cologne V6 in the 1995-1996 Ford Explorer and the 4.0L Ranger, and many of those trucks spent their lives towing. When one of them howls at highway speed in fourth, comes apart with a cooked overdrive band, or shows a front gearset with discolored pinions, the overdrive planetary is the part to replace. This one is new old stock, never installed and sold outside its original box, under interchange number A56580C (also listed as 56580C, 5R5225BN and 56-4R-545-HP). The planetary alone is included, as pictured.
Ford rated the 4R55E for 550 ft-lb, against 440 for the light-duty 4R44E, by beefing up the drive components for the 4.0L. The basic layout stayed the same as the A4LD: an overdrive section sitting ahead of the three-speed C3 gear train. This planetary is the heart of that front section. With the overdrive one-way clutch holding, it turns as a locked unit in the lower three gears. When the overdrive servo applies the band and holds the sun gear, the carrier drives the ring gear faster than the input, giving a 0.75 fourth gear. The coast clutch, inside the overdrive drum, can also lock the set for engine braking. On a heavy Explorer pulling a trailer in fourth, this gearset carries every bit of torque the 4.0L makes, which is why heat damage shows up here first.
Rule out hydraulics first. Sonnax notes that a worn coast clutch valve and EPC problems in this family can take out fourth, kill engine braking and break bands, all without a bad gearset, so put a gauge on the unit with our line pressure checking guide. If fourth feels soft, our article on shift flare versus slip helps you tell a band or valve problem from a mechanical one. A noise that follows the overdrive switch at a fixed road speed points to the front gearset. With the unit open, rough or loose pinions, chipped teeth or heat color on the carrier mean it is time for this part.
This listing is not tied to one year. The 4R55E was used from the 1995 model year in the Explorer and 4.0L Ranger until the five-speed 5R55E replaced it for 1997. The overdrive planetary carries the same interchange across the 4R44E, 4R55E, 5R44E and 5R55E, which makes it easy to source, but the 4R55E overdrive drum is larger than the 4R44E drum, so do not assume the surrounding parts swap the same way. The 5R55W and 5R55S use a different overdrive planet ratio and are not a match. Hold your old carrier up to the photo, or send us your year and VIN and we will confirm it. All related parts are on our 5R55-family transmission parts page.
While the front of the case is open, check the overdrive drum for an out-of-round or heat-damaged band surface; the 4R55E overdrive drum assembly is available if yours is scrap. Replace the front thrust washers and bearings, verify the overdrive one-way clutch freewheels one way only, and set end play before final assembly. A new overdrive band, coast clutch frictions and seals are part of doing this job once; the 4R55E master rebuild kit for 1995-1996 includes them. If the truck tows, an auxiliary cooler is cheap protection for the new gearset. Flush the cooler and lines, then refill with MERCON V and set the level hot.
| Fits | 4R55E |
| Part type | Planetary |
| Condition | New Other (See Details) |
| Brand | OEM |
| Ships | From the USA |
| Warranty | 1-year |
It is the overdrive planetary used in the 4R55E and its 4R44E, 5R44E and 5R55E relatives. Compare your old carrier to the photo, or send your year and VIN and we will confirm the match.
This overdrive planetary carries the same interchange number for both. The 4R55E overdrive drum and clutch capacity are larger, so check the parts around it separately.
New old stock, never installed, sold outside its original box. Only the planetary shown is included.
Heat and load in fourth gear are the usual causes, especially when towing. A slipping overdrive band, low fluid or a valve body leak that lets the band or coast clutch slip will overheat the front gearset.
Front thrust washers and bearings, the overdrive band, and coast clutch frictions and seals. Inspect the overdrive drum and one-way clutch, and flush the cooler before refilling with MERCON V.
