Yukon Gear Master Overhaul Kit for Ford 8.8in IRS Rear Differential Large Bearing

Yukon YK F8.8-IRS-L Ford 8.8in IRS Rear Differential Complete Rebuild Kit

The YK F8.8-IRS-L from Yukon Gear and Axle is the purpose-built master overhaul kit for the Ford 8.8-inch independent rear suspension differential with the larger 3.544-inch OD carrier bearing, used in 2006 and newer Ford Mustang, Expedition, Explorer, and Lincoln Navigator and related models. When your Ford 8.8 IRS rear differential develops noise, play, or fluid leaks, the YK F8.8-IRS-L provides every component for a thorough complete rebuild kit. Timken bearings, a full shim set, all seals, and hardware are included. The YK F8.8-IRS-L is the right kit for rebuilding the late-model Ford 8.8 IRS differential.

Features and Benefits

• Designed for the Ford 8.8in IRS differential with 3.544in OD carrier bearing in 2006+ applications
• Timken carrier bearings and races for reliable precision and long service life
• Timken pinion bearings and races for accurate pinion depth and quiet operation
• Complete pinion depth shim set for correct gear mesh and contact pattern
• Complete carrier shim set for proper backlash and bearing preload
• Pinion seal and output seals to prevent fluid leaks
• Ring gear bolts, pinion nut, and crush sleeve for a complete hardware refresh
• Gear marking compound with brush and thread-locking compound included
• Differential cover gasket included
• Compatible with OEM and aftermarket ring and pinion gear sets
• All components quality-verified to Yukon Gear standards

Vehicle Fitment

Specifications

What Is Included

• Timken front carrier bearing and race
• Timken rear carrier bearing and race
• Timken inner pinion bearing and race
• Timken outer pinion bearing and race
• Pinion seal
• Axle seals (pair)
• Complete pinion depth shim set
• Complete carrier shim set
• Ring gear bolt set
• Pinion nut
• Crush sleeve
• Thread-locking compound
• Gear marking compound with brush
• Differential cover gasket

Frequently Asked Questions

What does IRS mean and what is the 3.544in OD carrier bearing spec?
IRS stands for Independent Rear Suspension. The Ford 8.8 IRS differential uses half-shafts instead of a solid axle. The "L" in YK F8.8-IRS-L denotes the larger 3.544-inch outer diameter carrier bearing used in 2006 and newer applications. Earlier IRS differentials use a smaller carrier bearing and require a different kit.

Does the YK F8.8-IRS-L include Timken bearings?
Yes. The YK F8.8-IRS-L includes Timken carrier bearings with races and Timken pinion bearings with races for industry-leading performance and durability.

Can I use this kit when installing aftermarket gears?
Yes. The complete shim set in the YK F8.8-IRS-L supports correct setup for both OEM and aftermarket ring and pinion ratios.

Is a cover gasket included?
Yes. A differential cover gasket is included in the YK F8.8-IRS-L kit for a complete rebuild.

Does this kit fit Ford Mustang GT500 models?
Yes. The YK F8.8-IRS-L fitment list includes multiple Shelby GT500 model years equipped with the Ford 8.8 IRS differential with the larger carrier bearing. Confirm bearing OD before ordering.

Will installing the YK F8.8-IRS-L void my vehicle warranty under the Magnuson-Moss Warranty Act?
Under the Magnuson-Moss Warranty Act, a vehicle manufacturer cannot void your warranty solely because an aftermarket part was installed. The warranty is voided only if the manufacturer proves the part caused the specific failure. Consult your warranty documents and a qualified professional.

What warranty does Yukon Gear provide?
Yukon Gear and Axle offers a limited warranty on the YK F8.8-IRS-L covering defects in materials and workmanship. Contact Yukon Gear for full terms.

Is professional installation recommended?
Yes. The Ford 8.8 IRS differential requires precise pinion depth, backlash, and bearing preload settings. A qualified drivetrain technician is strongly recommended.

Installation Instructions

1. Raise and support the vehicle on jack stands. Drain differential fluid.
2. Remove the half-shafts and any necessary bracketry to access the differential.
3. Remove the differential cover and clean all mating surfaces.
4. Mark bearing caps for correct reinstallation orientation.
5. Remove carrier bearing caps and extract the carrier assembly.
6. Press old carrier bearings off the carrier and discard with races.
7. Remove the pinion nut and companion flange, then drive out the pinion shaft.
8. Press out old pinion bearings and remove the pinion seal from the housing.
9. Clean all bearing bores and housing surfaces thoroughly.
10. Press new Timken pinion bearing races into the housing.
11. Determine correct pinion shim and install new inner pinion bearing and shim on the pinion shaft.
12. Install new crush sleeve and outer pinion bearing. Install new pinion seal. Thread on pinion nut and torque to specification while monitoring rotating torque.
13. Press new Timken carrier bearings onto the carrier. Install carrier with correct shims to achieve specified backlash.
14. Verify gear contact pattern with marking compound. Adjust shims as needed.
15. Torque bearing caps to spec. Install new gasket and cover, fill with correct gear oil, reinstall half-shafts, and lower the vehicle.

Proposition 65 Warning: This product can expose you to chemicals including lead, which is 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.