Carrier and pinion bearings, races, shims, crush sleeve, pinion seal, and hardware to set up or regear a 2009-and-down Ford 8.8 rear differential.
A Ford 8.8 rear end that howls when you are on the throttle, whines when you let off at highway speed, or leaves a wet ring of gear oil around the pinion yoke is telling you its bearings and seal are done. This USA Standard Gear ZK F8.8 master overhaul kit holds every bearing, race, shim and seal inside the center section of a 2009-and-down solid-axle 8.8, the axle found under the F-150, Mustang, Explorer, Ranger 4.0L, Bronco and the Crown Victoria and its Mercury and Lincoln twins. Use it to freshen a noisy stock axle or as the setup kit when you put in a new ring and pinion.
The 8.8 pinion rides on two tapered roller bearings held under preload by a collapsible crush sleeve and the pinion nut. The carrier sits on two more tapered bearings, and shims behind those bearings set both backlash and side preload. Pinion depth is set by a shim under the inner pinion bearing race. When any of those bearings wears, the pinion moves under load, the gear contact pattern walks off the teeth, and the noise starts. This kit replaces all four bearings and their races, gives you the shims to reset depth and preload, and supplies the crush sleeve, pinion nut, pinion seal, ring gear bolts, thread locker, gasket and gear marking compound with a brush.
Drive at the speed where the noise is loudest, then note whether it changes on throttle, on coast or when you turn. A sound that changes in turns is usually a wheel bearing at the axle end, which this kit does not cover. A center-section whine tied to load is pinion or carrier bearings. Pull the cover, check backlash with a dial indicator and rock the pinion yoke up and down; any play there means the pinion bearings are worn. If the Traction-Lok is also slipping, rebuild it at the same time with the Ford M-4700-B clutch kit.
This kit is for the 8.8-inch solid rear axle through the 2009 model year. Ford also used 8.8 ring gears in independent rear suspensions (Explorer, Mountaineer, Aviator, Expedition, Thunderbird, Mustang Cobra) and in the front IFS of 4x4 F-150s and Expeditions; those are separate ZK F8.8 variants with different bearings, so match the kit to your axle. The 2015-and-later Super 8.8 with the 12-bolt cover is also different. For a 2010-and-later solid axle, send us your year and axle tag. More 8.8 parts are on the hard parts page.
If you want Timken bearings instead, look at the Timken 8.8 master bearing kit.
| Fits | 2009-and-down Ford 8.8" rear differential (F-150, Explorer, Ranger, Mustang, Crown Victoria) |
| Ring Gear | 8.8 inch |
| Bearings | Koyo carrier and pinion bearings and races |
| Includes | Pinion seal, crush sleeve, pinion nut, ring gear bolts, full shim kit |
| Also Included | Thread locker, marking compound with brush, gasket |
| Not Included | Axle shaft bearings and axle seals |
| Mfr Part Number | ZK F8.8 |
| Item Weight | 6 lb |
| Ships | From the USA |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
No. It covers the center section only: pinion and carrier bearings and races, shims, crush sleeve, pinion nut, pinion seal and ring gear bolts. Axle shaft bearings and seals are sold separately.
The 2002-up Explorer uses an independent rear 8.8, which takes a different ZK F8.8 variant. This kit is for the solid-axle 8.8. Check your rear suspension and axle tag before ordering.
Yes. It has everything you need to set pinion depth, backlash and preload on a new ring and pinion, including marking compound to read the pattern.
You need a bearing puller or press, race drivers, a dial indicator for backlash and an inch-pound torque wrench to check pinion preload. Setting up gears without them is guesswork.
Use the grade on your axle tag or in the owner's manual; many 8.8 axles take 75W-140 or 75W-85. Add friction modifier first if the axle is a Traction-Lok.
