Ford 9.75 Rear Differential Bearing Kit R9.75FRL Koyo

This is the Motive Gear R9.75FRL rear bearing kit for the Ford 9.75-inch rear axle, the twelve-bolt housing Ford put under half-ton trucks and full-size SUVs from mid-1999 through 2010. It is the bearing-and-setup kit, not a ring and pinion set: Koyo tapered carrier bearings and races, inner and outer pinion bearings and races, pinion seal, crush sleeve and pinion shim pack, pinion nut, gasket material, thread locker, and a brush with gear marking compound so you can read the pattern before you button the housing up.

Fitment covers 1999-2010 F-150 including the 2004 F-150 Heritage, the 1999 F-250 light duty, 1999-2010 Expedition, 2000-2004 Excursion, 1999-2002 E-150 Econoline and Club Wagon, 2003-2006 E-150, 1999-2002 E-250 Econoline, plus 1999-2010 Lincoln Navigator and the 2002 Blackwood. The bearing numbers in this kit are the updated ones that supersede the OE variations Ford used in 2007-2010 housings. It cross-references Transtar 763B004A, NTN RA316B, Motive Gear R9.75FRLT, and USA Standard Gear ZBKF9.75-B and ZBKF9.75-C. Measure the ring gear before ordering - Ford also ran the 8.8-inch axle in the same trucks and none of these bearings interchange.

The job runs in the usual order. Mark the carrier caps left and right, pull the carrier and set the old carrier shims aside, then press the old races out of the housing and drive the new Koyo races in square until they seat. Set pinion depth with the shim pack behind the inner bearing, install the crush sleeve, and collapse it slowly on the pinion nut until you reach rotating torque - once you go past it the sleeve is scrap and you start over with a new one. Drop the carrier back in, set backlash with the side shims, then paint the ring gear and roll it to check the drive and coast pattern before final assembly.

What kills a 9.75 is usually towing heat and a leaking pinion seal running the lube down. Once the pinion bearings brinell you get a whine that changes with load, and by then the races are pitted and replacing bearings alone will not fix it - the races have to come out too, which is why this kit ships both halves of every bearing. Motive Gear backs it with a 1-year / 50,000-mile warranty.