Yukon Gear Master Overhaul Kit For 06+ Ford 8.8in Irs Passenger Cars or SUVs w/ 3.544in OD Bearing
If the independent rear end under your Ford SUV or car has started to howl on the highway, drone under light throttle, or weep gear oil from the pinion or the half-shaft side seals, the bearings and seals in the 8.8 IRS center section are usually the cause. This Yukon Gear & Axle YK F8.8-IRS-L master overhaul kit is built for the 2006-and-later Ford 8.8 independent rear differential that uses a pinion bearing race with a 3.544 in outside diameter. It replaces every bearing and seal inside the carrier housing in one part number, whether you are quieting a worn stock unit or setting up a new ring and pinion.
The 8.8 IRS uses the same ring gear size as the solid-axle 8.8, but the gears live in a separate carrier housing bolted to the subframe, and the half shafts plug into the differential through stub axles with their own side seals. The pinion turns on two tapered roller bearings held under preload by a collapsible crush sleeve and the pinion nut. The carrier rides on two more tapered bearings, and the shims behind them set backlash and carrier preload. A shim under the inner pinion race sets pinion depth. Once any of those bearings wears, the pinion walks under load, the contact pattern moves off the center of the teeth, and gear noise follows. Yukon packs this kit with Timken carrier and pinion bearings and races, the pinion seal, both side seals, a complete shim kit, ring gear bolts, pinion nut, crush sleeve, thread locker, marking compound with brush, and the cover gasket.
Pinpoint the speed where the noise peaks and check whether it changes on and off the throttle. A noise that comes and goes with steering is more likely a hub or wheel bearing; IRS rears also have stub axle bearings, which are not part of this kit and should be checked at the same time. With the vehicle safely supported, grab the pinion flange and try to move it up and down; any play means the pinion bearings are worn. Drain the oil and look for glitter or chunks before you order.
Yukon lists this kit for 2006-and-up Ford 8.8 IRS units in passenger cars and SUVs with a 3.544 in OD pinion bearing. Ford built more than one 8.8 IRS, and Yukon makes a separate SUV kit for units with a 3.250 in pinion race, so measure the old race or check its bearing number before you order. The 2015-and-later Super 8.8 in the Mustang and F-150 uses larger bearings and a different kit, the Yukon 2015-up 8.8 overhaul kit. A solid-axle 8.8 takes the 09-and-down 8.8 kit. If you are unsure, send us the year, VIN and axle code from the door tag. More axle rebuild parts are on the rebuild kits page.
| Brand | Yukon Gear & Axle |
| Part number | YK F8.8-IRS-L |
| Fits | Yukon Gear Master Overhaul Kit For 06+ Ford 8.8in Irs Passenger Cars or SUVs w/ 3.544in OD Bearing |
| 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.
Measure the outside diameter of the old pinion bearing race, or read the bearing number stamped on it. This kit is for 3.544 in races. Yukon sells a separate 8.8 IRS SUV kit for 3.250 in races.
Yes. Yukon lists side seals in this kit along with the pinion seal, carrier and pinion bearings and races, shims, crush sleeve, pinion nut, ring gear bolts, thread locker, marking compound and gasket.
No. The 2015-up Super 8.8 has larger bearings and a longer pinion, so it uses the 2015-up 8.8 overhaul kit instead.
No. The stub axle bearing is a separate part. If you have noise that changes in turns, check it and the hub bearings before blaming the differential.
A press or bearing puller, race and seal drivers, a dial indicator for backlash and an inch-pound torque wrench for pinion preload. Gear setup without them is guesswork.
