4R100 Master Rebuild Kit 1998-2005, new and ready to install. Fits the 4R100. Ships fast from the USA.
A 4R100 that slips on the 2-3 when it is hot, flares into overdrive under a load, or leaves black, burnt-smelling fluid and friction material in the pan is past the point where a fluid change or a solenoid will help. That is the moment owners of Ford F-250 and F-350 Super Duty trucks, Excursions and E-Series vans with the 7.3L Power Stroke, 5.4L or 6.8L V10 start shopping for a 4R100 master rebuild kit. This new kit covers 1998 through 2005 units and puts the soft parts for a complete overhaul in one box, pictured with frictions, steels, a band, the filter, the gasket set and the seal and O-ring package.
The 4R100 is Ford's heavy-duty four-speed built from the E4OD, with a stronger pump, a stamped-steel coast clutch drum and, in most applications, a PWM converter clutch. Every clutch pack in it, coast, overdrive, forward, direct, intermediate and low/reverse, depends on rubber seals and gaskets holding pressure and on friction material that has not been glazed by heat. After a few hundred thousand miles of towing those parts are tired all at once. A master kit lets the builder reseal every circuit and renew every pack in one teardown instead of fixing the clutch that failed first and waiting for the next one.
Rule out the outside problems before you order a kit. Clean and inspect the case connector, scan for codes, and put a gauge on line pressure, because a sensor or EPC fault can make a healthy unit shift soft. If the pan shows friction material and the shifts still slip with correct pressure, the unit is coming out. Our E4OD and 4R100 rebuild cost guide explains what the teardown decides, and the rebuild wear points guide lists the hard parts to check while it is apart.
The listing covers the 4R100 from 1998 through 2005. Ford made running changes inside that span, so match the kit to the parts on your bench. Transmission Digest documents a PTO and a non-PTO coast clutch drum: the PTO drum holds three frictions, the non-PTO drum two, and the later 1C3Z-7G387BA PTO drum needs an oil dam washer that must not go on the earlier drums. Converter clutch control also split between PWM and on/off pumps. Count your coast clutch plates, note whether the case has a PTO port, and compare your parts to the photo, or send us your year and VIN. Our 4R100 vs E4OD guide walks through those checks, and every part for this unit is on the E4OD/4R100 collection page.
Inspect the drums, bushings, planetaries and the pump before reassembly; the kit renews soft parts and does not fix a scored pump pocket or a blued planet. Replace the OD piston return spring retaining ring with a locking spiral ring such as the Sonnax Sure Lock, since Transmission Digest documented a 4R100 that destroyed its overdrive clutches when the original ring walked out. Use the center support gasket and torque its screws in stages to the Sonnax spec. Soak new frictions in MERCON V, set clutch clearances, and prime the pump at install. If the overdrive planet shows heat damage, replace it with a 4R100 planetary, and add a 4R100 shift kit while the valve body is out. Flush the cooler and lines, and install a rebuilt torque converter so old debris does not return.
| Fits | 4R100 1998-2005 |
| Part type | Master Rebuild Kit |
| Condition | New |
| Brand | OEM |
| Ships | From the USA |
| Warranty | 1-year |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
It is listed for the 1998-2005 4R100. Many E4OD parts look the same but the drums, pump and some plate counts differ, so E4OD units should use an E4OD kit matched to their years.
No. A master kit is soft parts. Install a rebuilt converter with any overhaul so debris from the failed unit is not pumped into the new clutches.
Yes. The PTO coast clutch drum uses three frictions instead of two and has its own thrust and oil dam parts. Count your plates and tell us if the unit has a PTO port.
Anything worn found at teardown: bushings, a scored pump, a heat-damaged planetary, plus a locking OD retaining ring and a shift kit. Flush the cooler and lines.
MERCON V. Fill, start the engine, cycle through the gears and set the final level hot in Park.
