Yukon Gear Master Overhaul Kit For 09 & Down Ford 8.8in Diff
A Ford 8.8 rear end that whines on the highway, groans on deceleration, or leaves gear oil on the driveway at the pinion is due for new bearings and a seal. The Yukon Gear & Axle YK F8.8-A master overhaul kit covers the 8.8-inch ring gear axle used through the 2009 model year under F-150 pickups, Mustangs, Rangers, Explorers, Broncos and the Crown Victoria family. It is a new kit with Timken bearings and races plus the shims and hardware to rebuild the center section correctly, whether you are just curing noise or installing new gears.
Ford introduced the 8.8 in 1983 trucks as the replacement for the 9-inch, and it became the rear axle under a long list of cars, trucks and SUVs. Unlike the 9-inch, the 8.8 is an integral carrier design: the gears live inside the axle housing behind a bolt-on cover, and the axle shafts are held in by C-clips on the ends of the shafts inside the carrier. The pinion is supported by two tapered roller bearings with preload set by a crush sleeve, and the carrier rides on two tapered side bearings with shims behind them that set backlash and side bearing preload. When those bearings wear, the pinion walks away from the ring gear under load and the whine or howl follows.
Yukon lists these parts in the YK F8.8-A:
Separate gear noise from wheel bearing noise first. On the 8.8, worn axle bearings hum and change when the truck leans into a turn, and a damaged axle shaft bearing surface is common on high-mileage F-150s. Raise the rear, drain the oil and look for metal on the magnet. Turn the pinion by hand and rock the yoke to feel for roughness or play. If the only complaint is chatter in parking lot turns, the fix is the Traction-Lok clutch kit, not a full overhaul. If you need side bearings only, the 8.8 carrier installation kit is the smaller option.
The YK F8.8-A is listed for the Ford 8.8-inch solid rear axle through the 2009 model year. That covers the bulk of 1983-2009 F-150, 1986-2009 V8 Mustang, 1991-2009 Ranger 4.0L, 1983-1996 Bronco, solid-axle 1991-2001 Explorer and many Panther-platform cars, but factory bearing and pinion changes happen, so match it to your axle tag or send us the year and VIN. Several 8.8 variants need a different kit: the 2015-up 12-bolt Super 8.8 uses the YK F8.8-D, and the front axle in 4x4 Expeditions and F-150s is a reverse-rotation unit served by the YK F8.8-REV. IRS SUVs and cars also use their own kit. Prefer Koyo bearings? The USA Standard ZK F8.8 is the alternative.
Pull the cover, remove the pinion shaft lock bolt and cross shaft, push the axles in and take out the C-clips before the shafts can slide out. Mark the bearing caps so they go back on the same side. A side bearing puller set removes the old carrier bearings without damaging the carrier. Set pinion depth with the shim under the inner pinion bearing, then tighten the pinion nut gradually while checking turning torque so the new crush sleeve is not over-crushed. Shim the carrier for backlash and preload and read the pattern with the supplied compound on both sides of the teeth. If you are changing ratio at the same time, a set such as the Yukon 8.8 4.11 gear set goes in with this kit. Refill with the gear oil grade on your axle tag or owner guide, and add friction modifier for Traction-Lok axles. Break new gears in with easy driving and no towing for the first few hundred miles.
| Brand | Yukon Gear & Axle |
| Part number | YK F8.8-A |
| Fits | Yukon Gear Master Overhaul Kit For 09 & Down Ford 8.8in 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.
Yukon lists the YK F8.8-A for 2009 and earlier 8.8 axles. For 2010-2014 vehicles, send us the year and VIN or the axle tag code and we will confirm the correct kit before you order. 2015 and newer uses the 12-bolt Super 8.8 kit.
No. The listed contents cover the center section: carrier and pinion bearings and races, pinion seal, crush sleeve, nut, shims, ring gear bolts, thread locker, marking compound and gasket. Axle bearings and seals are sold separately.
This kit handles the bearings and setup parts around the carrier. The clutch packs inside a Traction-Lok are a separate kit. If you hear chatter in tight turns, rebuild the clutches at the same time.
Use the gear oil grade listed on your axle tag or owner guide; Ford 8.8 axles commonly call for 75W-140 or 75W-85 synthetic depending on the vehicle. Traction-Lok axles also need friction modifier.
You need a bearing puller, a press or bearing drivers, an inch-pound torque wrench for pinion preload and a dial indicator for backlash. Without those, have a driveline shop do the setup.
