Yukon Gear 8.8in Ford 3.55 Rear Ring & Pinion Install Kit 2.25in OD Axle Bearings and Seals
A Ford 8.8 rear that whines at 50-60 mph, a Mustang or F-150 that needs a 3.55 to wake up acceleration, or a high-mile axle you want to rebuild once and forget: this Yukon Gear & Axle package, part number YGK2217, puts everything for the job in one box. It combines a 3.55 ratio ring and pinion, a Yukon master install kit with Timken bearings, and 2.25 in. OD axle bearings with seals.
The 8.8 uses a hypoid pinion supported by two tapered bearings and a crush sleeve, driving an 8.8 in. ring gear bolted to the carrier, with C-clips holding the axle shafts in. Gear noise usually starts when pinion bearing preload fades, the gear mesh moves, and the contact pattern wanders off the center of the teeth. At that point bearings and gears tend to wear out together, and the axle bearings at the outer ends of the housing are often just as tired. This kit replaces all three: gears, center section bearings and small parts, and the wheel-end bearings and seals.
A 3.55 ratio is a popular middle choice in the 8.8. It pulls noticeably harder than a 3.08 or 3.27 while keeping highway rpm reasonable, which makes it a common upgrade for V8 Mustangs and a sensible ratio for half-ton trucks on stock-size tires.
Raise the axle, spin each wheel and listen. A rough or rumbling wheel points to an axle bearing; a whine that only shows up under load points to the gears or pinion bearings. Pull the cover and check the teeth and the drain plug magnet. If you want a gears-only option, we also carry the YG F8.8-355 3.55 gear set by itself. Find your current ratio on the door or axle tag, and count the ring and pinion teeth if the axle has been changed.
Yukon builds this kit for the Ford 8.8 rear with a 10-bolt cover and a 10-bolt ring gear, with a 3.250 in. OD inner pinion bearing and 2.25 in. OD axle bearings. That covers the standard solid-axle 8.8 found under many F-150, Mustang, Ranger, Explorer, Expedition and Crown Victoria models, but Ford used more than one inner pinion bearing and axle bearing size over the years. It does not fit the 2015-and-up Super 8.8 with a 12-bolt cover, the IRS 8.8, or the reverse rotation front 8.8. Measure the old axle bearing and pinion bearing or check the axle tag, or send your year and VIN and we will confirm. More parts for this axle are in our rebuild kits section.
Set pinion depth with the new pinion shim, then build preload by tightening the pinion nut against a new crush sleeve in small steps. Yukon's set-up chart for the 8.8 lists 14-19 in-lb of preload on new pinion bearings and 60 ft-lb on both the ring gear bolts and the bearing caps. Check backlash and paint the teeth to confirm the drive and coast pattern. If you would rather not fight a crush sleeve, the 8.8 crush sleeve eliminator lets you set preload with shims.
For a Traction-Lok carrier, now is the time to refresh the clutches with a Traction-Lok clutch rebuild kit and add friction modifier with the fill. Use 75W-140 or 75W-85 gear oil as specified for your vehicle. Break the gears in the way Yukon calls for: easy driving for the first 15-20 miles and a cool-down, no hard launches for 100 miles, no towing for 500 miles, and an oil change at 500 miles.
| Brand | Yukon Gear & Axle |
| Part number | YGK2217 |
| Fits | Yukon Gear 8.8in Ford 3.55 Rear Ring & Pinion Install Kit 2.25in OD Axle Bearings and Seals |
| Type | Differential Install 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.
Most 2014-and-earlier F-150 trucks with the 8.8 rear use the 10-bolt cover this kit is built for, but bearing sizes changed over the years. Confirm 2.25 in. OD axle bearings and a 3.250 in. inner pinion bearing, or send your VIN and we will check.
No. The 2015-and-up F-150 uses the Super 8.8 with a 12-bolt cover, which needs different gears and kits.
No. You reuse your existing carrier, open or Traction-Lok, as long as it is in good condition. Inspect the carrier and side gears while the axle is apart.
Only with a Traction-Lok or other clutch-type limited slip. Add it with the gear oil to stop chatter in turns.
Drive gently for 15-20 miles and let the axle cool, avoid hard acceleration for 100 miles, do not tow for 500 miles, then change the gear oil.
