If you have ever watched a Jeep on a trail with one front wheel spinning freely in the air while the other three sit motionless, you have seen exactly why locking differentials exist. An open differential, which is what most non-Rubicon Jeeps come with, sends power to the wheel with the least resistance. On pavement, that is fine because all four tires are in contact with the ground. Off-road, where wheels routinely lose traction or lift entirely, an open differential becomes a traction-killing liability. Lockers solve this problem fundamentally, and they are one of the single most impactful upgrades you can make to a Jeep's off-road capability.
At American Fusion Wheels in Shawnee, KS, we install locking differentials on everything from stock-height Wranglers used for weekend trail rides to fully built competition crawlers. This guide explains how lockers work, the different types available, what they cost, and how they affect daily driving.
How an Open Differential Works (And Why It Fails Off-Road)
A standard open differential splits torque equally between two wheels on the same axle, but it allows them to rotate at different speeds. This is essential for turning on pavement, where the outer wheel travels a longer path than the inner wheel. The problem arises when one wheel has significantly less traction than the other. Because the differential always takes the path of least resistance, it sends all available torque to the spinning wheel and effectively zero torque to the wheel that still has grip. The result is a Jeep sitting motionless while one tire spins uselessly. Off-road, this happens constantly. Rocks, ruts, mud, and uneven terrain create situations where at least one wheel on each axle has reduced traction.
What a Locking Differential Does
A locking differential, or locker, mechanically forces both wheels on an axle to rotate at the same speed regardless of traction differences. When both wheels are locked together, torque goes to whichever wheel has grip. If both have grip, both drive. If one is in the air, the other still receives full power. This is a transformative change in off-road capability. A Jeep with lockers front and rear can maintain forward momentum in situations where an open-diff Jeep is completely stuck.
The Rubicon edition of the Wrangler and Gladiator comes from the factory with electronic lockers front and rear, which is one of the primary justifications for its premium price. For Sport, Sahara, and other non-Rubicon models, adding aftermarket lockers is the single best bang-for-your-buck off-road upgrade available.
Types of Locking Differentials
Selectable Lockers (Air or Electric)
Selectable lockers give you the best of both worlds: an open differential for street driving and a fully locked differential for off-road use. You activate them with a switch, and they engage mechanically to lock both axle shafts together. When disengaged, the differential operates as a standard open diff with no impact on daily driving.
ARB Air Locker is the most popular selectable locker for Jeeps. It uses a small onboard air compressor to pneumatically engage the locking mechanism. The ARB system is extremely reliable, with decades of proven performance in competition and expedition use worldwide. ARB lockers for Dana 30 and Dana 44 axles cost $800-$1,100 for the locker unit, plus $250-$400 for the air compressor kit if you do not already have one. Installation labor runs $600-$900 per axle, including the air line routing and switch wiring.
Eaton E-Locker uses an electromagnetic mechanism instead of air. It is the same technology used in the factory Rubicon lockers. The E-Locker is slightly easier to install because it does not require an air compressor or air lines, just electrical wiring. Eaton E-Lockers cost $700-$1,000 per axle. For Jeep owners who want selectable locking without the air system complexity, the E-Locker is an excellent choice.
Automatic Lockers
Automatic lockers are always engaged and only unlock when a speed difference between the two wheels forces them to differentiate, such as during turns on pavement. They do not require any switches, compressors, or wiring. The tradeoff is that they affect daily driving behavior.
Detroit Locker is the most aggressive automatic locker available. It is a gear-driven unit that locks both axle shafts together under power and allows differentiation during turns through a cam mechanism. The Detroit Locker produces a characteristic clicking sound during turns on pavement, and it can cause the vehicle to push (understeer) in corners. It is incredibly strong, completely mechanical with no parts to fail electronically, and costs $400-$700 per axle. Installation labor is the same as other lockers. The Detroit Locker is best suited for the rear axle of trail-dedicated Jeeps that see regular off-road use. We do not recommend it for front axles on daily-driven Jeeps because it affects steering feel significantly.
Auburn Gear ECTED Max is a hybrid design that functions as an automatic locker off-road but can be electronically disengaged for street driving. This gives it similar versatility to a selectable locker while maintaining a simpler mechanical design. Auburn Gear units cost $600-$900 and are available for most Jeep axle configurations. They are a strong middle-ground option for Jeep owners who want automatic engagement on the trail with the ability to return to open-diff behavior on the highway.
Limited-Slip Differentials (LSD)
Limited-slip differentials are not true lockers, but they deserve mention because they are often compared. An LSD uses clutch packs or gears to transfer some torque to the wheel with more traction when the other wheel slips. They do not fully lock both wheels together. Common LSD options include the factory Trac-Lok that comes in some Jeep trims and aftermarket units from Yukon and Eaton. LSDs are a step up from open differentials but fall well short of a true locker in off-road capability. They are best suited for mild off-road use, snow, and slippery conditions where full locking is unnecessary.
Front vs Rear: Where to Install First
If your budget allows only one locker, install it in the rear axle first. Here is why: the rear axle handles the majority of driving force, and in most off-road situations, rear traction is the primary limitation. A rear locker provides approximately 70 percent of the benefit of locking both axles. It keeps the rear end driving forward consistently, and the open front differential can usually find enough traction to steer and pull.
Adding a front locker second completes the system and unlocks the full potential of four-wheel drive. With both axles locked, all four tires drive simultaneously, which is transformative on rock crawling, steep muddy climbs, and rutted terrain. However, a front locker on a daily-driven Jeep affects steering feel, particularly with automatic lockers. Selectable front lockers avoid this issue entirely because they stay open on the street.
For Kansas City area Jeep owners who primarily run moderate trails and backroads, a rear locker alone may be all you need. For those building serious trail machines, front and rear lockers together with proper gearing create a fundamentally different vehicle.
How Lockers Affect Daily Driving
Selectable lockers (ARB, Eaton E-Locker) have zero impact on daily driving when disengaged. You will not notice any difference in handling, noise, or tire wear on your commute through Shawnee, on I-35 to downtown KC, or on weekend highway trips. This is why selectable lockers are the most popular choice for dual-purpose Jeeps.
Automatic lockers (Detroit, Aussie Locker, Spartan) produce clicking during turns and can cause the rear end to feel skittish on wet or icy pavement. The clicking is the unlocking mechanism working as designed, and it is noticeable but not dangerous. However, if you drive in Kansas City winter conditions with ice and snow, an automatic rear locker requires more attentive driving because it can cause sudden oversteer when it locks unexpectedly on slippery surfaces.
Limited-slip differentials have minimal daily driving impact and are nearly transparent in normal use.
Cost Summary for Kansas City Installations
- ARB Air Locker + compressor (one axle): $1,650-$2,400 installed
- ARB Air Locker (second axle, compressor already installed): $1,400-$2,000 installed
- Eaton E-Locker (one axle): $1,300-$1,900 installed
- Detroit Locker (one axle): $1,000-$1,600 installed
- Auburn Gear ECTED Max (one axle): $1,200-$1,800 installed
- Yukon/Eaton LSD (one axle): $800-$1,400 installed
Combining locker installation with a regear saves significant labor cost because the differential is already disassembled. If you are planning both, schedule them together. At American Fusion Wheels, we offer package pricing for combined locker and gear installs that saves $400-$600 compared to doing them separately.
Brand Recommendations by Use Case
- Daily driver that hits trails on weekends: ARB Air Locker or Eaton E-Locker (rear first, then front)
- Dedicated trail rig, minimal street use: Detroit Locker rear, ARB or E-Locker front
- Overlanding and moderate off-road: Eaton E-Locker rear, LSD front
- Budget build, maximum trail benefit: Detroit Locker rear only
- Snow and light off-road only: LSD rear, open front
Lockers and Other Modifications
Lockers work best as part of a coordinated build. Pairing lockers with appropriate gear ratios ensures your engine can deliver power effectively to all four locked wheels. Running lockers with too-tall gearing on large tires puts excessive load on the locker internals and the axle shafts. A properly geared Jeep with lockers is not just more capable, it is also more reliable because every component operates within its designed parameters.
Traction control and electronic stability systems on JL and JT Jeeps interact with aftermarket lockers. When a selectable locker is engaged, the vehicle's traction control should be turned off to prevent the system from fighting the locked differential. Most JL and JT Jeeps handle this automatically when you engage the factory off-road modes, but aftermarket lockers may require manual traction control deactivation.
Ready to build your Jeep? Contact American Fusion Wheels at (913) 291-2027 or visit us at 12310 W 62nd Ter, Shawnee KS. We will evaluate your axles, discuss your trail goals, and recommend the right locker setup for your Jeep and your budget.
