A rear locker changes the JL's off-road capability more dramatically than almost any other single upgrade — but your rear axle (Dana 35 vs Dana 44) determines which lockers are available, and those axle differences also determine whether a locker is the right investment or whether an axle upgrade should come first.
The axle situation on the JL is the critical starting context. JL Sport and Sport S models come with a Dana 35 rear axle — a solid, competent axle for street and mild trail use, but lighter-duty than the Dana 44. The Sahara also ships with the Dana 35 in most configurations. The Rubicon (and the Rubicon 392) gets the Dana 44, which is the significantly stronger choice for technical trail use. If you're on a Sport or Sahara and considering a locker, you need to decide whether you're locking a Dana 35 long-term or upgrading to a Dana 44 carrier down the road — because the lockers are not interchangeable.
For the Dana 35 (Sport/Sahara), the two realistic choices are the ARB Air Locker ($799) or the Detroit Truetrac ($449). The Truetrac is not technically a locker — it's a helical gear limited-slip differential that provides significant bias toward the wheel with traction under load, but does not achieve full lock. For mild-to-moderate trail use on a rig that sees pavement regularly, the Truetrac is the right choice: it's transparent on-road, requires no compressor or electrical system, and the $449 price point is accessible. For genuine rock crawling where complete drive wheel lock is required, the Truetrac falls short.
The ARB Air Locker for the Dana 35 ($799) delivers full lock on demand. ARB's air locker engages via an onboard air compressor (required separately — budget $150–$300 for a basic unit) and disengages cleanly when the air is released. The on-road behavior when unlocked is stock-equivalent. The ARB is the correct choice for a Dana 35 build that sees sustained technical terrain. be realistic: a Dana 35 with a locker will eventually meet a trail that exceeds the axle's shaft strength. Know your terrain.
For the Dana 44 (Rubicon), both the ARB Air Locker ($849) and Eaton ELocker ($649) are full-lock solutions with different engagement mechanisms. The ARB requires a compressor; the Eaton ELocker engages electrically via a dash switch. The ELocker is the value choice for a Rubicon build — $200 less than the ARB, no compressor required, reliable engagement, and the electrical install is cleaner. The ARB's advantage is faster engagement response and the ability to share the compressor with ARB lockers front and rear, plus tire inflation duties.
Rubicon owners note: the factory Selec-Trac II transfer case includes an electronic rear locker. If your Rubicon already has the factory locker, evaluate whether an aftermarket locker adds meaningful capability before spending $649–$849.
| Part | Vendor | Est. price |
|---|---|---|
| ARB Air Locker RD100 — Dana 35 (JL Sport/Sahara) | ARB | ~$799 |
| ARB Air Locker RD156 — Dana 44 (JL Rubicon) | ARB | ~$849 |
| Eaton ELocker — Dana 44 (JL Rubicon) | Eaton | ~$649 |
| Detroit Truetrac — Dana 35 (JL Sport/Sahara) | Eaton Detroit Truetrac | ~$449 |
Written and maintained by an AZ wheeler and driveway wrencher. Always cross-reference your factory service manual — modifications affect vehicle safety and warranty. Work at your own risk.