4R70W Sprag Clutch, remanufactured and ready to install. Fits the 4R70W. Ships fast from the USA.
If your 1998-or-later F-150, Expedition, Navigator, Crown Victoria, Grand Marquis, Town Car or Mustang with the 4R70W flares on the 1-2 shift, feels like it drops into neutral in second, or you pulled the unit down and found the intermediate one-way clutch chewed up, this is the assembly most people are searching for when they type in "4R70W sprag." It is a remanufactured reverse clutch drum with the intermediate one-way clutch (the mechanical diode) already packed into it, built for 1998-up units, with hardened drive lugs. You get the drum and the holding device as one tested piece instead of trying to save a race that the old one-way clutch already damaged.
The 4R70W uses two one-way clutches: a low roller clutch in the planetary for first gear, and the intermediate one-way clutch for second. In second the intermediate clutch pack applies, and the one-way clutch locks against it so the reverse sun gear is held and the gearset gives you the 2nd ratio. In third and fourth it simply freewheels, which is why a bad unit usually shows up in second only. The diode rides on lugs at the top of the reverse clutch drum, and that same drum carries the reverse clutch pack and is wrapped by the overdrive band. According to Suncoast, Ford replaced the earlier roller-type intermediate clutch with the mechanical diode in 1998 to get more holding capacity and longer life, and it notes that both designs fail under high-rpm conditions.
A slipping second can also come from the intermediate clutch pack, its piston seals, or oil lost at the overdrive servo. Sonnax ties many intermediate one-way clutch, overdrive band and forward clutch failures to the overdrive servo pin wearing its case bore, so check that bore during teardown. Read codes, check fluid level and condition, then follow our 4R70W F-150 shift problems guide to separate hydraulic faults from hard parts. If you are already apart and the diode spins freely both ways or locks both ways, the assembly is done.
This drum is listed for 4R70W units from 1998 on, the mechanical diode era, which covers the later F-150, Expedition, Navigator, Crown Victoria, Grand Marquis, Town Car and Mustang applications. Pre-1998 units used the roller-type intermediate clutch, and the 2004 and later 4R75 updates changed other parts of the gear train, so compare your old drum to the photo, check the lug pattern and diode style, and send us your year and VIN if you are unsure. Browse everything for this unit in our 4R70W parts collection.
| Fits | 4R70W |
| Part type | Sprag Clutch |
| Condition | Remanufactured |
| 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 the reverse clutch drum with the intermediate one-way clutch (mechanical diode) already installed, sold as one remanufactured assembly with hardened lugs.
It is listed for 1998 and later units, which use the mechanical diode. Earlier units used a roller-type intermediate clutch, so compare your parts to the photo or send us your year and VIN before ordering.
A 1-2 flare, a slipping or neutral second gear, and often P0732 on OBD-II trucks, with first and third still pulling normally.
Intermediate clutch frictions, seals and gaskets from a rebuild kit, plus anything debris damaged such as the sun shell or planetary. Check the overdrive servo pin bore as well.
Ford specifies MERCON V for 1998-2008 4R70W and 4R75W units. Some 2009-and-later 4R75E vehicles call for MERCON LV, so check your owner guide or dipstick.
