Master bearing rebuild kit for the Ford 7.5-inch 10-bolt rear axle with Koyo carrier and pinion bearings, races, crush sleeve, shims, pinion nut and seal.
If your Ranger, Bronco II, early Explorer, Aerostar or V6 Mustang has a rear end that whines at cruise, howls when you get on or off the gas, or rumbles more as speed climbs, the Ford 7.5-inch axle is telling you its bearings are worn. The Motive Gear R7.5FRMK is a master installation kit for that axle. It gives you every bearing, race, shim and hardware piece needed to rebuild the center section or set up a new ring and pinion in one pass, with Koyo tapered bearings throughout.
The Ford 7.5 is a 10-bolt-cover, C-clip rear axle with a 7.5-inch ring gear. The pinion rides on two tapered roller bearings, a large inner (head) bearing and a smaller outer (tail) bearing, with a collapsible crush sleeve between them. Tightening the pinion nut crushes the sleeve until the bearings reach the right rotating drag. The carrier spins on two side bearings, and shims behind them set both carrier preload and ring gear backlash. When any of these bearings wear, the pinion is allowed to move under load. The gear contact pattern shifts, and the axle starts to whine on drive, on coast, or both. Left alone, a loose pinion bearing will chew up the ring and pinion, which turns a bearing job into a gear job.
Axle shaft bearings and axle seals are not part of this kit. Those are sold separately and are worth doing while the C-clips are out.
Drive the vehicle on a smooth road and note whether the noise follows the drive cycle. Pinion bearing noise usually changes on and off throttle. Carrier bearing noise tends to be a steadier rumble. A wheel bearing noise often changes when you swerve gently left and right to load each side. With the rear raised and the driveshaft off, grab the pinion yoke and check for any up-and-down or in-and-out movement. Pull the cover, drain the oil into a clean pan and look for metal. If the ring gear teeth are pitted or flaked, plan on new gears too. The Ford 7.5 3.73 ring and pinion with master bearing kit packages both in one box.
Motive Gear catalogs this kit as a standard-rotation rear master kit for the Ford 7.5-inch differential with a 7.5-inch ring gear, 10 ring gear bolts and a 28-spline pinion. Listed applications include the 1983-2011 Ford Ranger, 1984-1990 Bronco II, 1991-1994 Explorer, 1990-1997 Aerostar, 1979-2010 Mustang with the 7.5 axle, 1978-1983 Fairmont and Zephyr, 1980-1997 Thunderbird and Cougar, Granada, Capri, Marquis and the 1984-1987 Mark VII. Many of these vehicles also came with the larger 8.8 axle depending on engine and options. Both use a 10-bolt cover, so do not go by bolt count. Read the tag under a cover bolt or measure the ring gear. If you are unsure, send us the year and VIN before ordering. Browse more axle components in our hard parts section.
| Axle | Ford 7.5-inch (10-bolt) rear differential |
| Kit type | Master bearing overhaul kit |
| Bearings | Koyo carrier and pinion bearings with races |
| Also includes | Crush sleeve, pinion nut, pinion seal, shim kit, marking compound |
| Fitment | Ford Ranger, Aerostar, Bronco II, Explorer, V6/small-V8 Mustang and other RWD Fords with the 7.5 ring gear |
| Reference | Motive Gear R7.5FRMK |
| Condition | New |
| Warranty | 1 year |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
It fits Ford 7.5-inch rear axles, which Ford used in many Rangers, the 1991-1994 Explorer, Bronco II and Aerostar. Some of those trucks came with the 8.8 instead. Check the axle tag or measure the ring gear, or send us the year and VIN.
No. It covers the pinion and carrier bearings, races, shims, crush sleeve, pinion nut, pinion seal, ring gear bolts, cover gasket and marking compound. Axle shaft bearings and seals are separate.
You can start with the original shim stack as a baseline, but new bearings rarely measure the same as the old ones. The kit includes pinion and carrier shims so you can correct pinion depth, preload and backlash.
Only if the teeth are pitted, chipped or show heavy wear. If the gears look good, a bearing rebuild with this kit is often enough to quiet the axle.
Use the grade listed in the owner's manual for your year, as Ford has changed the spec over time. If the axle has a Traction-Lok limited slip, add the friction modifier Ford calls for.
It is a precision job. Expect to need a dial indicator, an inch-pound torque wrench for preload, a press or bearing puller and patience to read gear patterns. Many owners buy the kit and have a driveline shop do the setup.
