Yukon Gear Dura Grip Positraction For Ford 8.8in w/31 Spline Axles
If your F-150, Explorer, Expedition, Ranger, Mustang or Crown Victoria spins one rear tire on wet pavement or a gravel ramp, the factory Traction-Lok clutches are usually worn out or the axle came open from the start. The Yukon Dura Grip YDGF8.8-31-1 is a complete replacement clutch-type positraction carrier for the Ford 8.8 inch ring gear axle with 31-spline axle shafts. Yukon lists it for all gear ratios, so you do not need a different case for 3.27, 3.55, 3.73 or 4.10 gears.
The stock 8.8 Traction-Lok uses a stack of clutch plates behind each side gear to tie the axle shafts to the carrier. When those plates glaze or wear thin, the axle behaves like an open differential and all the torque goes to the tire with the least grip. The Dura Grip uses the same basic idea with a heavier package: a high-strength nodular iron case, forged 4320 chromoly spider gears and composite clutch plates that hold preload longer than worn factory steels. Under power it pushes both tires; in a turn the clutches slip so the outside wheel can run faster. It is fully rebuildable, so when the clutches eventually wear you replace the plates rather than the whole carrier.
Jack up the rear with the transmission in neutral and turn one tire by hand. If the other tire turns the opposite way with little resistance, the clutches are gone or the axle is open. If it chatters in turns, try a fresh fill with friction modifier first; our Traction-Lok chatter fix walks through that. Then confirm the axle: the 8.8 has a 10-bolt cover, and 31-spline shafts are 1.32 inch diameter while the 28-spline shafts are 1.29 inch. Our 28 vs 31 spline guide shows how to tell them apart without pulling a shaft. The 2015-and-up Super 8.8 has a 12-bolt cover and 34-spline shafts and does not take this carrier.
Yukon's application chart for this part covers the 31-spline Ford 8.8 in 1983-2014 F-150 rear axles, 1997-2014 Expedition and 1998-2005 Navigator, 1991-2010 Explorer and Mountaineer, Explorer Sport Trac, 2003-2005 Aviator, 1999-2011 Ranger, 1994-2014 Mustang including the 1999-2004 and 2006-2011 IRS cars, 2003-2011 Crown Victoria, Grand Marquis and Town Car, and the 2009-2014 F-150, Expedition and Navigator reverse-rotation front axle. Ford mixed 28 and 31 spline across many of these years, so count the splines or send us your year and VIN, and check the axle tag. If you need the smaller shafts, the 28-spline Dura Grip is the matching part, and if you want a full automatic locker for trail use, see the Grizzly Locker for the 31-spline 8.8. Owners of 2015-up trucks need the Super 8.8 34-spline Trac Loc. More carriers are in our hard parts category.
Pull the cover, drain the oil, remove the pinion cross shaft lock bolt and cross shaft, push the axles in and take out the C-clips, then slide the shafts out a few inches. IRS and reverse front units use half shafts held in by circlips instead of C-clips, so follow the service manual for those. Mark and remove the bearing caps and lift the carrier out, keeping the side shims in order. Move the ring gear to the Dura Grip with new bolts and press on new carrier bearings; the Yukon 8.8 carrier installation kit covers bearings, shims and hardware, and a master overhaul kit adds pinion bearings, seal and crush sleeve if the gears are noisy. Set backlash to the Yukon chart range of .006-.011 inch and check the pattern. Yukon recommends high-grade non-synthetic GL-5 gear oil plus its limited slip additive and says synthetic oil can make the unit noisy or aggressive. Our friction modifier guide covers dosing. Drive easy for the first few hundred miles while the clutches bed in.
| Brand | Yukon Gear & Axle |
| Part number | YDGF8.8-31-1 |
| Fits | Yukon Gear Dura Grip Positraction For Ford 8.8in w/31 Spline Axles |
| Type | Differentials |
| 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.
No. The 2015-up Super 8.8 has a 12-bolt cover, larger bearings and 34-spline shafts. This carrier is for the earlier 10-bolt 8.8 with 31-spline axles.
Yukon lists it for all ratios used in the 8.8, so you can keep your current gears or regear at the same time without buying a different case.
The 31-spline shaft is 1.32 inch diameter and the 28-spline is 1.29 inch. Many trucks and cars were built with either, so count the splines or measure the shaft, or send us your year and VIN.
A non-synthetic GL-5 gear oil with Yukon limited slip additive. Yukon says synthetic oil is not recommended with the Dura Grip and can cause noisy or aggressive engagement.
The ring gear can move to the new case with new bolts. Carrier bearings are pressed on and usually damaged on removal, so plan on a carrier installation kit.
Yukon lists it for the 2009-2014 F-150, Expedition and Navigator reverse front 31-spline 8.8. Confirm your front axle code before ordering.
