USA Standard Master Overhaul Kit For The Ford 8.8 Diff
The Ford 8.8 has been under F-150s since 1983, V8 Mustangs from 1986, solid-axle Explorers, Rangers with the 4.0L, Broncos and the Crown Victoria family, so plenty of them are now well past 150,000 miles. When one starts to sing on the highway, hum on deceleration or drip gear oil off the pinion, the USA Standard Gear ZK F8.8 master overhaul kit is the complete set of center-section wear parts for a 2009-and-down 8.8. Inside: Koyo carrier and pinion bearings and races, a pinion seal, a complete shim kit, ring gear bolts, a pinion nut, a crush sleeve, thread locker, marking compound with a brush and a cover gasket.
In the 8.8 the drive pinion is held by two tapered roller bearings, and a collapsible crush sleeve sets their preload when the pinion nut is torqued. The differential carrier rides on a pair of side bearings, with shims between the bearing races and the housing setting both backlash and carrier preload. A shim behind the inner pinion bearing positions the pinion relative to the ring gear. The 8.8 is a C-clip axle, so the axle shafts are retained inside the carrier by clips on the cross shaft. As the bearings wear, preload is lost and the pinion deflects under torque; the tooth contact moves off center and the axle gets loud. This kit gives you new bearings at all four positions plus the shims and hardware to put the setup back where it belongs.
A noise that gets louder in one direction of a turn is almost always an axle shaft bearing at the wheel end, which is not part of this kit. A noise tied to load (on throttle or on coast) is the pinion or carrier bearings or the gear mesh. Lift the rear, rock the pinion yoke up and down, and feel for play. Drain the oil and look at it in good light. If the Traction-Lok chatters in tight turns too, plan to rebuild it in the same job with the Ford M-4700-B Traction-Lok clutch kit.
This kit is listed for the 2009-and-down Ford 8.8 in. rear axle. Ford also built 8.8 ring gear axles as independent rear suspensions (Thunderbird, 1999-2004 Cobra, 2003-up Explorer, Mountaineer, Aviator, Expedition and Navigator) and as the front IFS axle in 4x4 F-150s and Expeditions; those use different bearings and different kits. For 2010 F-150 and 2010-up Mustang solid axles, use the ZK F8.8-B kit, and the 2015-up Super 8.8 with the 12-bolt cover is different again. The axle tag on a cover bolt shows the ratio and build code; send us that, or your year and VIN, if you want fitment checked. All of our differential kits are on the rebuild kits page.
| Brand | Yukon Gear & Axle |
| Part number | ZK F8.8 |
| Fits | USA Standard Master Overhaul Kit For The Ford 8.8 Diff |
| Type | Differential Overhaul Kits |
| Condition | New |
| Ships | Same business day (in stock), from the USA |
| Warranty | 1-year |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
It is listed for 2009-and-down Ford 8.8 in. rear axles. 2010 F-150 and 2010-up Mustang solid axles take the ZK F8.8-B, and the 2015-up Super 8.8 with the 12-bolt cover needs its own kit.
No. The 2003-and-later Explorer, Mountaineer and Aviator use an IRS 8.8 with different bearings. This kit is for the solid-axle 8.8.
Koyo carrier and pinion bearings with races. The kit also has the pinion seal, shim kit, ring gear bolts, pinion nut, crush sleeve, thread locker, marking compound with brush and a cover gasket.
Only if it chatters or no longer locks. Since the carrier is already out, it is the cheapest time to fit new clutch packs, and you need friction modifier in the refill either way.
A carrier bearing puller or press, race and bearing drivers, a dial indicator for backlash and an inch-pound torque wrench for pinion preload. Without them the setup is a guess.
No. Axle shaft bearings and seals at the wheel ends are separate parts.
