4R100 Clutch Drum, used and ready to install. Fits the 4R100. Ships fast from the USA.
This is a used, original-equipment coast clutch drum for the Ford 4R100, the heavy-duty four-speed behind 1998-2004 F-250 through F-550 Super Duty trucks, the Excursion and E-Series vans with the 7.3L Power Stroke, 5.4L or 6.8L V10. If you are hunting for one, you probably opened the front of the transmission and found a drum with chewed lugs, a scored bushing or bearing journal, or a coast clutch pack that has turned to powder. A sound factory drum gets the overdrive section back together for far less than a complete unit.
The 4R100 is built in two sections: a simple overdrive planetary up front and a C6-derived three-speed main box behind it. The coast clutch drum lives in the overdrive section, right behind the pump. It houses the coast clutch piston and plates, and when that clutch applies it locks the overdrive planetary so the front section can carry torque in both directions. That is what gives you engine braking on a long downgrade with overdrive cancelled or a lower range selected, and on a 4R100 with a PTO the same drum also carries the PTO drive gear.
The drum rides on the pump's stator support. On every 4R100 the bushing or bearing journal on that support faces forward, the opposite of the E4OD, because the PTO gear hanging on the coast drum adds load that has to be supported. Ford made the 4R100 coast drums from stamped steel instead of the cast iron used on the E4OD, and the coast clutch steels got wider teeth to match.
Sonnax lists no engine braking, OD planetary failure and an overheated OD area among the common complaints in this family, and lube flow to the front section is part of that story.
Rule out electrical first. A coast clutch solenoid or a corroded case connector can disable engine braking on a perfectly good drum, so read codes and check the solenoid pack before tearing in; our E4OD and 4R100 common problems guide walks through the resistance checks and connector failures. If the electronics test good and the pan shows coast clutch material, pull the pump and inspect the drum: look for cracked or flattened lugs, a worn bushing or rough bearing, scored sealing ring lands and a piston that will not hold air.
The listing identifies this as a 4R100 coast clutch drum. It is a 4R100 part, not an E4OD part: the E4OD uses the cast iron drum with its bushing toward the back of the bore and will not interchange. Within the 4R100, Ford built non-PTO and PTO drums and revised both. The first non-PTO drum (YC3Z-7G387AA) used a bushing and two frictions; it was later changed to a bearing (1C3Z-7G387AA), still with two frictions. The PTO drums carry a large gear and three frictions, and the late PTO drum (1C3Z-7G387BA) uses an oil dam washer the earlier PTO drums must not have. Compare gear, support style and friction count against the drum you removed, or send us your year and VIN before ordering. Our 4R100 vs E4OD guide walks through each version, and the full lineup of front-section parts is on the E4OD and 4R100 collection page.
| Fits | 4R100 |
| Part type | Clutch Drum |
| Condition | Used |
| 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.
No. The E4OD uses a cast iron coast drum with its bushing toward the back of the bore, and the stator support on an E4OD pump is laid out the opposite way. A 4R100 drum belongs in a 4R100 with a 4R100 pump.
A PTO drum has a large gear mounted to it and holds three frictions. A non-PTO drum has no gear and holds two. Check the drum you removed and the case: a 4R100 with a PTO opening and a PTO installed needs the PTO drum.
New coast clutch frictions and steels, piston seals, the stator support sealing rings, a filter, and the thrust washer if your drum is the bushing type. Flush the cooler so old clutch debris does not return to the new pack.
Loss of engine braking with overdrive off or in manual low ranges, slip around the overdrive shift, burnt clutch material in the pan, and front-end noise from a worn drum bearing or bushing.
Mercon V automatic transmission fluid. Fill to the full mark at operating temperature after the rebuild and recheck after the first drive.
There is no drum-specific relearn. Clear any stored codes after repairs and drive the truck through all ranges so the computer can adapt to the fresh clutch pack.
