Ford 8.8 Explorer Rear Axle Swap (Full Guide)
The most popular XJ rear axle swap. Salvage 1995-2001 Ford Explorer 8.8" axles are cheap, strong, come with disc brakes and often LSD; bolt-in for 33s/35s.
The Ford 8.8 swap is the most common XJ rear axle upgrade. Donor: 1995-2001 Ford Explorer, Explorer Sport Trac, or Mountaineer. The Explorer 8.8 has:
- 8.8" ring gear (vs 7.625" D35).
- 31-spline C-clip shafts (C-clip eliminator kits are available).
- Disc brakes standard.
- Often factory limited-slip (the lettered "L" on the axle code).
- Roughly the same width as the D35 (5/8" narrower per side; ~1.25" total).
Donor sourcing: salvage yards $150-400. Look for low-mileage donor and verify the gear ratio (stamped on the tag) matches what you want — common ratios are 3.55, 3.73, 4.10.
Swap requirements:
- Cut off Ford spring perches (they're spring-under; XJ is spring-under too but the perch position differs).
- Weld on new XJ spring perches at correct perch-to-perch dimension (43.5625"). Use a kit (Mountain Off-Road, IRO, Ruff Stuff) for pre-cut perches and locating jigs.
- Brake line: Ford's hard line is metric flare, XJ master cylinder uses different flare. Adapter or new line required.
- Driveshaft: stock XJ rear shaft will need shortening (~1-2") or replacement with custom length. CV-style shaft with SYE is recommended.
- Emergency brake: Ford uses different cable end. Need adapter or relocated cable.
Width: 8.8 is roughly 5/8" narrower per side. Wheels with 3.75-4" backspace work; stock XJ wheels with 5.25" backspace tuck the tire too far in.
Gear ratios: must MATCH the front D30. If you have a 3.55 front, you need a 3.55 rear. If swapping in 4.10s, you need 4.10 in both axles.
Cost: $600-1200 all-in for parts (donor axle, perch kit, brake line, driveshaft mods, U-bolts).
The 8.8 is the de facto rear axle for any serious XJ build. Excellent strength, comes with discs, comes with LSD often, and the price is right.
Why it works
- Cheap and abundant donors
- Disc brakes included
- Often LSD included
- 31-spline strong shafts
- Right width for XJ
Trade-offs
- Welding required
- Time-intensive swap
- Brake line adapter needed
- Driveshaft modification needed
Tools required
- MIG welder
- cutoff wheel
- grinder
- metric sockets
- torque wrench
- floor jack
- jack stands
- brake bleeding tools
Parts
| Part | Vendor | Est. price |
|---|---|---|
| Ford 8.8 Explorer rear axle (salvage) | Salvage yard | ~$300 |
| Mountain Off-Road 8.8 swap kit (perches/brackets) | Mountain Off-Road | ~$280 |
| IRO 8.8 swap kit with truss | Iron Rock Off Road | ~$380 |
| Tom Wood's custom CV driveshaft | Tom Wood's | ~$380 |
Sources
- All-Inclusive Ford 8.8 Swap Guide - NAXJA
- Mountain Off-Road 8.8 Swap Kit
- IRO 8.8 Swap Kit
- Ford Explorer 8.8 Swap Data - NAXJA
Related
- Dana 44 Rear Swap (TJ Rubicon, Aftermarket)
- Currie / Ten Factory Crate Axles
- All Jeep Cherokee XJ guides & tools
- Browse the full DIY database
Written and maintained by an AZ wheeler and driveway wrencher. How we source guides. Always cross-reference your factory service manual — modifications affect vehicle safety and warranty. Work at your own risk.