Rear Locker for the TJ — Chrysler 8.25", Dana 35, and Dana 44

The rear axle choice in the TJ is a meaningful build variable. Dana 35 units (base 1997–2002 models) use C-clip axle retention — when a side shaft breaks under load, the wheel can separate from the vehicle. The Dana 35's small ring gear and thin side shafts are the limiting factor. Adding a locker to a Dana 35 and running 35" tires on technical terrain is a scenario where side shaft failure becomes a real probability, not a theoretical one. The correct answer is either upgrading to a Chrysler 8.25" (a common axle swap) or installing a Chrome-Moly axle upgrade from Superior Axle before adding the locker.

The Chrysler 8.25" rear axle (Sport and Sahara trim 1997–2006) is a substantially stronger unit — larger ring gear diameter, full-float flange (no C-clips), and a track record as a reliable trail rear end. Most serious TJ builds run the 8.25" or swap to a Dana 44 (from a Rubicon or other source). For the 8.25", the Detroit Locker ($499) is the value pick: a mechanical locker that engages automatically under torque differential and disengages on deceleration. On-trail behavior is predictable once you know what to expect — slight ratcheting on tight pavement turns is the trade-off for consistent engagement when one wheel lifts.

The ARB Air Locker ($799 for 8.25") is the selectable option: locked when you want it, open diff when you don't. For a rig that mixes street driving and trail use, selectable is the correct choice — an always-on locker like the Detroit noticeably changes driving behavior on pavement, including oversteer tendency in corners. The ARB requires an air compressor and solenoid kit (sold separately, approximately $250); plan for the additional install time and wiring.

Rubicon owners with the factory Dana 44 rear already have a stronger axle foundation — the ARB Air Locker RD100 is the premium choice and pairs well with the Rubicon's factory ARB front air locker for a matched selectable system.

Steps

1. Drain the rear differential fluid completely.
2. Raise the rear axle on jack stands with both rear tires off the ground.
3. Remove both rear wheels and brake drums or calipers (set aside; do not disconnect brake lines).
4. Remove rear axle shafts — on the Chrysler 8.25", remove the differential housing cover and retaining pin to release C-clips on Dana 35; on 8.25" (full-float) remove the axle retaining plate bolts.
5. Remove the differential carrier assembly from the housing.
6. Press out existing spider gears and side gears; install locker unit per manufacturer instructions.
7. Reinstall carrier assembly with new bearing preload as specified. Set backlash to factory spec (0.005"–0.008" on Chrysler 8.25").
8. For ARB Air Locker: route air line through axle housing per ARB instructions; connect to solenoid and compressor.
9. Install new diff cover gasket or apply RTV; torque cover bolts to 20–25 ft-lbs in a cross pattern.
10. Reinstall axle shafts and retaining hardware; torque to spec.
11. Refill with 80W-140 gear oil (Chrysler 8.25": 2.5 pints); use friction modifier if TJ has a limited-slip OEM unit.
12. Reinstall brake hardware, wheels; torque lug nuts to 95 ft-lbs.
13. Test on dry pavement at low speed to verify engagement feel before trail use.

Why it works

• Chrysler 8.25" with a Detroit or ARB locker is a durable, capable rear end for moderate to aggressive trail use
• ARB selectable design preserves on-road driving behavior — unlocked for streets, locked for trails
• Detroit Locker provides automatic engagement with no compressor, wiring, or solenoid
• Rubicon Dana 44 with ARB creates a matched selectable front/rear system
• Dramatically improves traction on side-hills, loose terrain, and one-wheel-up obstacle lines

Trade-offs

• Dana 35 C-clip retention is a failure risk under locker loads — upgrade axle shafts or replace the axle before locking it
• ARB Air Locker requires compressor, solenoid wiring, and air line routing — significant additional install complexity and cost
• Detroit Locker causes noticeable handling changes on pavement — understeer in tight turns, potential for rear-end stepping in low-grip corners
• Installation requires differential expertise — incorrect bearing preload or backlash will damage the ring and pinion
• The locker alone does not compensate for regear needs — 35" tires still require 4.56 or 4.88 gears regardless of locking differential

Tools required

• floor jack
• jack stands
• socket set
• torque wrench
• bearing puller
• pinion depth gauge
• dial indicator
• ring gear installation tool
• RTV sealant

Parts

Sources

• JeepForum — TJ Rear Locker Options: Dana 35 vs 8.25 vs Dana 44
• ARB Air Locker Chrysler 8.25 Installation Guide
• Pirate4x4 — Dana 35 Rear Axle Strength Discussion

Related

• Re-Gearing the TJ — 4.56, 4.88, and 5.13 Ratios
• TJ Skid Plates — What the Factory Already Covers, What It Doesn't, and the Tummy Tuck
• All Jeep Wrangler TJ 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.