Lock both axles and the JK becomes a different machine on rock — traction is no longer a question of luck or momentum. The rear lock is the higher-priority install; the front matters most when you're on off-camber ledges or loose boulder fields.
The JK's axle configuration splits by trim. Non-Rubicon JKs get a Dana 30 front and Dana 44 rear. Rubicon models come with Dana 44 front and rear plus factory electric lockers. If you have a Rubicon with functioning factory e-lockers, that's already the spine entry — you don't need an aftermarket locker unless the factory units have failed. For Sport, Sport S, and Sahara owners, both front and rear aftermarket lockers are on the table.
ARB Air Locker (Selectable): The cleanest option for a street-and-trail JK. When disengaged, the carrier behaves exactly like an open diff — no binding in turns, normal tire wear, no noise. Engaged via a dashboard-mounted switch connected to an ARB compressor, it locks both axle shafts solid. The tradeoff is complexity: you're adding a compressor, air lines, and a solenoid to the diff, which are additional failure points. The ARB is the right call for any build that spends significant time on pavement between trail runs.
Eaton ELocker (Selectable, electric): No compressor required — the lock engages via an electric actuator wired to the cab. More straightforward than an air system, close to ARB's street behavior when disengaged, and proven across a wide installed base on Jeep applications. The ELocker engages at low speed only (under 15 mph for most applications) — not a limitation in trail driving but worth knowing.
Detroit Locker (Full-time): Locks automatically under throttle, unlocks briefly during deceleration to allow cornering. Zero complexity, zero maintenance, mechanical reliability. The cost is noise — Detroits clunk on-road during slow turns, and the engagement behavior can feel unpredictable to drivers who haven't used one before. The right call for a dedicated trail rig that rarely sees urban driving.
Install the rear locker first. In technical terrain, the rear axle is the primary driver — rear traction is what gets you up a ledge; front traction is what keeps the front from sliding off a line. A rear locker alone transforms the JK from a traction-challenged stock setup into a capable trail machine. Add the front when you're ready to tackle off-camber and boulder fields.
The Dana 44 rear on non-Rubicon JKs uses a 30-spline shaft — confirm this before ordering. Non-Rubicon Dana 44 rears (2007–2018) run a 3.73 factory gear ratio in most Sport/Sahara trims; Rubicons run 4.10. Verify your ratio before pairing with a regear order.
Locker installation requires setting ring-and-pinion backlash and bearing preload correctly — this is not a typical backyard install unless you've done differential work before. Plan for 6–8 hours with a bearing press and a methodical approach to pattern reading, or budget for a shop that does axle work regularly (not a general tire shop). Incorrect preload causes premature bearing failure; incorrect backlash causes gear noise and accelerated ring-and-pinion wear.
When installing an ARB Air Locker, run the air lines before buttoning up the axle. The most common post-install complaint is a kinked or chafed air line that develops a slow leak months later.
| Part | Vendor | Est. price |
|---|---|---|
| ARB Air Locker RD100 (Dana 30 front, 27-spline) | ARB | ~$699 |
| ARB Air Locker RD118 (Dana 44 rear, 30-spline) | ARB | ~$749 |
| Eaton ELocker Dana 44 Rear (2007–2018 JK) | Eaton | ~$689 |
| Detroit Locker Dana 44 Rear (2007–2018 JK) | Detroit Locker | ~$549 |
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.
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