The Traction Problem
Open differentials, what most Jeeps come with, send power to the wheel with least resistance. On pavement, this is fine. Off-road, it means your spinning wheel gets all the power while the wheel with traction gets nothing.
Understanding Your Options
Open Differential
What it does: Allows wheels to spin at different speeds (necessary for turning). Power goes to the path of least resistance.
Off-road: Terrible. One wheel in the air means you're stuck.
Limited Slip Differential (LSD)
What it does: Uses clutch packs or gears to transfer some power to the wheel with more grip. Not a full lock.
- Pros: Works automatically, no driver input needed
- Cons: Limited effectiveness, clutches wear over time
- Best for: Light off-road, daily driving, snow
- Cost: $400-800 installed
Automatic Locker
What it does: Mechanically locks both wheels together under power, unlocks during turns.
- Pros: Always working, no engagement needed, affordable
- Cons: Noisy on street, affects handling, can be unpredictable
- Best for: Dedicated trail rigs, budget builds
- Examples: Detroit Locker, Spartan Locker, Aussie Locker
- Cost: $200-600 installed
Selectable Locker
What it does: Driver-controlled lock. Open on-road, locked off-road at the push of a button.
- Pros: Best of both worlds, no street compromise
- Cons: Expensive, more complex, requires driver awareness
- Best for: Dual-purpose builds, daily drivers that wheel hard
- Examples: ARB Air Locker, Eaton E-Locker, Factory Rubicon
- Cost: $1,500-2,500 installed
Comparison Chart
| Feature | LSD | Auto Locker | Selectable |
|---|---|---|---|
| Street Manners | Excellent | Poor | Excellent |
| Off-Road Traction | Moderate | Excellent | Excellent |
| Cost | $400-800 | $200-600 | $1,500-2,500 |
| Complexity | Low | Low | High |
| Maintenance | Moderate | Low | Low-Moderate |
| Predictability | High | Moderate | High |
Front vs Rear: Where to Start
Always start with the rear. Here's why:
- Rear lockers provide the most traction improvement
- Front lockers affect steering significantly
- Many trails can be conquered with rear locker only
- It's cheaper to do one at a time
Front Locker Considerations
Front lockers require more driver skill. When locked:
- Steering becomes heavy and vague
- The Jeep wants to go straight
- Turning requires more input and planning
For front lockers, selectable is strongly preferred over automatic for this reason.
Our Recommendations
Light Off-Road / Snow / Casual Use
Rear LSD: Minimal compromise, helps in slippery conditions. Yukon Dura Grip or Auburn ECTED are good choices.
Regular Trail Use, Daily Driver
Rear Selectable Locker: ARB Air Locker or Eaton E-Locker. Full capability when needed, no compromise on-road.
Dedicated Trail Rig
Rear Auto Locker, Front Selectable: Detroit or Spartan in the rear, ARB in the front. Best capability for the money.
Budget Build
Rear Lunch Box Locker: Spartan Locker or Aussie Locker. Under $300, installs in an afternoon, massive improvement over open diff.
Common Questions
Will a locker hurt my daily driving?
Auto lockers: yes, noticeably. Selectable lockers: not at all when unlocked.
Do I need lockers for 35" tires?
Need? No. Will they help? Absolutely. Bigger tires without improved traction means you're just spinning bigger wheels.
ARB vs Eaton?
ARB uses compressed air (requires compressor). Eaton uses electricity. Both work excellently. ARB is more proven; Eaton is simpler to install.
The Bottom Line
For most Jeep owners who trail regularly, a rear selectable locker is the best investment. It provides massive capability improvement with zero street compromise. If budget is tight, a rear lunch box locker gets you 80% of the capability for 20% of the cost.