Yukon Gear Dura Grip Positraction For Ford 8.8in w/31 Spline Axles

Yukon Gear DuraGrip Limited Slip for Ford 8.8 Inch Differential with 31 Spline Axles

Ford F-150, Expedition, Explorer, Bronco, and Crown Victoria owners with 31-spline rear axle shafts now have a direct upgrade path with the YDGF8.8-31-1 Yukon Gear DuraGrip limited slip differential. Part number YDGF8.8-31-1 is engineered for the Ford 8.8 inch rear differential equipped with the heavier-duty 31-spline axle shafts found in trucks, full-size SUVs, and higher-performance configurations of the Mustang. The YDGF8.8-31-1 is compatible with all gear ratios available for the Ford 8.8 platform, making it a universal solution for vehicles from 1978 through 2017 across the entire Ford 8.8 application range. Built with forged 4320 chromoly spider gears and composite clutch packs inside a nodular iron carrier, the YDGF8.8-31-1 delivers consistent, predictable limited slip action that improves both daily traction and towing stability.

Features and Benefits

• Fits Ford 8.8 inch rear differential with 31-spline axle shafts
• Compatible with all gear ratios on the Ford 8.8 platform
• 4-spring, clutch-style positraction for smooth progressive torque transfer
• Forged 4320 chromoly steel spider gears cut for maximum tooth strength
• Nodular iron carrier case for structural durability under load
• Composite clutch packs reduce chatter and extend service life
• Fully rebuildable design with available clutch pack rebuild kits
• Assembled in the United States
• Replaces worn factory Trac-Lok or open differential carriers
• One-year warranty against manufacturer defects

Vehicle Fitment

Specifications

What Is Included

• One fully assembled DuraGrip positraction differential carrier
• Pre-installed composite clutch packs and 4-spring preload assembly
• Forged 4320 chromoly spider gears installed

Frequently Asked Questions

What is the difference between YDGF8.8-31-1 and YDGF8.8-28-1?
The only difference is axle spline count. The YDGF8.8-31-1 is for Ford 8.8 axles with 31-spline shafts, which are found in heavier-duty applications including F-150, Expedition, Explorer, and the Mustang Cobra and Shelby variants. The YDGF8.8-28-1 fits 28-spline applications such as base Mustang and Ranger.

Does YDGF8.8-31-1 fit the 2007 to 2014 Ford Expedition?
Yes. The YDGF8.8-31-1 fits 1997 through 2014 Ford Expedition with the 8.8 inch rear axle and 31-spline axle shafts.

Will this work with my 2007 to 2014 Ford Mustang Shelby GT500?
Yes. The YDGF8.8-31-1 fits the 2007 through 2014 Mustang Shelby GT500 which uses the Ford 8.8 rear with 31-spline axles.

Does YDGF8.8-31-1 fit all gear ratios?
Yes. This unit is compatible with all available gear ratios for the Ford 8.8 inch differential, including 2.73, 3.08, 3.27, 3.31, 3.55, 3.73, 4.10, and others.

What gear oil is required?
Use high-grade non-synthetic GL-5 75W-90 gear oil for normal street use. For towing or cold climates, 75W-140 is also acceptable. Add Yukon LSD additive (OILADD) to prevent clutch chatter on engagement.

Can I rebuild the YDGF8.8-31-1 when the clutches wear?
Yes. The DuraGrip design is fully rebuildable. Replacement composite clutch packs and springs are available so you can refresh the unit without buying a complete new carrier.

Does the Magnuson-Moss Warranty Act protect my truck after installation?
Under the Magnuson-Moss Warranty Act, installing YDGF8.8-31-1 does not automatically void your vehicle warranty. The dealer must demonstrate that this specific part directly caused any failure for which warranty service is denied.

Will the YDGF8.8-31-1 affect my truck's traction control or ABS systems?
No. As a mechanical limited slip differential, the YDGF8.8-31-1 is transparent to the vehicle's electronic systems. ABS and traction control systems operate via wheel speed sensors and are not affected by the type of differential carrier installed.

Installation Instructions

1. Drain differential fluid and remove cover, driveshaft, and axle shafts.
2. Mark bearing caps before removal for correct reinstallation orientation.
3. Remove caps and extract the original carrier assembly with side bearing shims.
4. Transfer the ring gear to the new YDGF8.8-31-1 carrier. Torque ring gear bolts to approximately 70 to 80 ft-lb for Ford 8.8.
5. Press side bearings onto the new carrier. Reinstall with original shims as baseline.
6. Measure backlash with a dial indicator; target is 0.008 to 0.015 inch for Ford 8.8.
7. Verify carrier preload and gear contact pattern with marking compound. Adjust shims as necessary.
8. Torque bearing caps to specification. Clean cover sealing surface.
9. Reinstall cover with RTV or new gasket. Fill with GL-5 gear oil and Yukon LSD additive.
10. Reinstall axle shafts and driveshaft. Road test and recheck fluid level at 500 miles.

Proposition 65 Warning: This product can expose you to chemicals including lead and lead compounds, which are known to the State of California to cause cancer and birth defects or other reproductive harm. For more information, go to www.P65Warnings.ca.gov.