When the trail gets tough and traction is at a premium, a standard open differential simply won’t cut it. For serious off-road enthusiasts who demand the ultimate in performance and control, a selectable locking differential is the gold standard. ARB Air Lockers have been the benchmark in this category for decades, offering unmatched durability and the convenience of on-demand traction at the flick of a switch. This technology allows you to drive in an open differential for normal conditions and lock both wheels together for maximum grip when you need it most.
Choosing the right Air Locker for your specific vehicle and axle setup is critical for a successful installation and years of reliable service. This roundup is designed to guide you through the key ARB models available, highlighting their specific applications and features. From iconic Jeep Dana 44 axles to robust Toyota 8-inch units and the legendary Ford 9-inch, we have covered the most popular options to help you make an informed decision for your next off-road upgrade.
The Ultimate ARB Air Locker Selection
- ARB RD117 Air Locking Differential
- ARB CKMA12 On-Board Air Compressor
- ARB RD114 Air Locking Differential
- ARB RD119 Ford 9 Inch 31 Spline Air Locker
- ARB RD132 Air Locker for Toyota 8″
- ARB RD246 Air Locker for Rubicon
- ARB RD142 Air Locker for Dana 44
- ARB RD129 Air Locker for Toyota 8.2-Inch
ARB RD117 Air Locking Differential
A top choice for Jeep JK owners and others running a Dana 44 axle, the RD117 is engineered for 30-spline full-floating axles with gear ratios of 3.73 and down. Its robust design is built to handle the stresses of serious rock crawling and technical terrain. The air-activated selectable locker provides the best of both worlds, offering smooth, predictable handling as an open differential on the street and instant, positive locking action off-road.
This unit effectively converts your axle from an open differential to a fully locked spool, ensuring both wheels receive equal power when engaged. This eliminates the one-wheel-spin phenomenon that can leave you stranded. The reliability of the ARB design is legendary in the off-road community, making this a cornerstone upgrade for any serious Jeep build focused on capability and performance.
ARB CKMA12 On-Board Air Compressor
No Air Locker system is complete without a reliable source of compressed air, and the CKMA12 is a high-performance 12-volt solution designed specifically for this task. Constructed entirely from lightweight, high-strength engineering-grade materials, this compressor is built for longevity and consistent performance. It is the heart of the system, providing the necessary air pressure to engage and disengage your locking differentials on command.
Beyond powering your lockers, this compressor is an incredibly versatile tool for any off-road vehicle. Its efficient design and quality components allow for quiet operation and a long service life. The hard-anodized cylinder bore reduces friction, enhancing durability. You can also use it to quickly re-inflate your tires after airing down for the trail, making it a multi-functional asset for your adventures.
ARB RD114 Air Locking Differential
The ARB RD114 is another robust option designed for applications using 30-spline axles. This model is intended for use with 4.10 and down gear ratios, making it a suitable choice for a range of vehicle setups that fall within these specifications. Like all ARB Lockers, it provides the driver with complete control, allowing you to choose between an open differential for daily driving and a fully locked differential for maximum traction.
The simple dash-mounted switch activation means you are always in command of your vehicle’s traction profile. This on-demand capability helps preserve driveline components and tire wear during normal operation while providing an immediate solution when obstacles appear. Its proven internal mechanism is known for strength and reliability under extreme loads.
ARB RD119 Ford 9 Inch 31 Spline Air Locking Differential
The legendary Ford 9-inch rear end is a favorite for high-horsepower and hard-use applications, and the RD119 is the perfect traction upgrade for it. This model is designed for 31-spline axles and is compatible with all gear ratios, offering great flexibility for various builds. The system uses compressed air, delivered via a durable nylon line, to engage the locking mechanism reliably and instantly.
It is important to note that this is just the differential unit itself. To operate the RD119, you will need to pair it with an ARB Air Compressor, which is sold separately. This allows you to select a compressor kit that matches your specific needs, whether you only plan to run a single locker or a more complex dual-locker system with additional air accessories.
ARB RD132 Air Operated Locking Differential for Toyota 8″
A staple in the Toyota off-road community, the RD132 is designed for the classic Toyota 8-inch front or rear differential, found in many older Land Cruisers, 4Runners, and Pickups. This model is built for 30-spline axles and is compatible with all gear ratios. Its reputation is built on an incredibly simple yet effective design that has been proven in some of the most remote and challenging environments on earth.
The reliability of this unit is a key reason why it remains a top choice for Toyota enthusiasts undertaking global expeditions or demanding trail rides. The ability to maintain normal driving manners until the locker is engaged makes the vehicle more versatile and safer to drive on a variety of surfaces. It is a fundamental upgrade for any serious Toyota 4×4 build.
ARB RD246 Air Locker Differential for Rubicon
The ARB RD246 is a specialized locker developed for the heavy-duty Dana 44 axles found in Jeep Wrangler JK and JL Rubicon models. Designed for 35-spline axle shafts, this is one of the strongest options available for this platform and is compatible with all gear ratios. It provides a significant traction advantage over even the factory-equipped electronic lockers, offering the proven reliability of ARB’s air-operated system.
For Rubicon owners looking to push their rigs to the next level, this locker is an excellent choice. It allows you to retain the use of your factory gears and axle housing while upgrading the core traction device to a unit known for its robust construction and consistent performance under extreme duress. It is the go-to for builders who demand the utmost strength.
ARB RD142 Air Locker for Dana 44
The ARB RD142 is a versatile air locking differential designed specifically for the popular Dana 44 axle assembly with 30-spline axles. This model serves as a critical upgrade for a wide range of 4×4 vehicles equipped with this axle, providing the legendary performance and control that ARB is known for. Its selectable nature ensures that your vehicle remains docile and easy to handle on paved roads.
When the terrain becomes challenging, the RD142 delivers immediate and positive locking action to drive both wheels equally. This eliminates wheel spin and provides the forward momentum needed to climb over obstacles and navigate through deep mud or sand. It is a trusted component for drivers who need dependable traction without compromising daily driveability.
ARB RD129 Air Locker for Toyota 8.2-Inch
Tailored for the modern Toyota platform, the RD129 is engineered for the 8.2-inch rear differential found in 2010 and newer 4Runner and FJ Cruiser models. This application-specific design ensures a perfect fit and optimal performance for these vehicles. It brings the benefit of a selectable locker to owners who want to significantly enhance the off-road capability of their late-model Toyota SUV.
This locker allows you to tackle more difficult trails with confidence, knowing you have a proven traction aid at your disposal. The ability to switch between an open and locked differential means you can enjoy a comfortable highway ride to the trailhead and then engage the locker to conquer technical sections that would otherwise be impassable. It is an ideal upgrade for the adventurous Toyota owner.
Buying Guide: How to Choose the Right ARB Air Locker
So, you’re thinking about stepping up your off-road game with an ARB Air Locker. That’s a solid move. I’ve been through the process myself, and it’s not just about picking the shiniest box off the shelf. Getting the right one means matching the locker to your specific rig and how you use it. Let’s talk about what really matters when you’re looking at the 8 best ARB Air Locker differential for serious off-road use.
First up, you need to know exactly what differential you’re replacing. This sounds basic, but it’s the most common trip-up. We’re not just talking about the vehicle model, like a Jeep Wrangler JK or a Toyota Tacoma. You need the specific axle model and gear ratio. Is it a Dana 44, a Toyota 8-inch, an AAM 9.25? This information is critical because ARB makes specific lockers for specific housings. Getting this wrong means a part that simply won’t fit. Your vehicle’s VIN or a quick look at the axle tag can usually give you the answers.
Next, consider your vehicle’s weight and your tire size. This is a big one. A heavy rig on 40-inch tires puts a lot more stress on components than a lighter one on 33s. While ARB lockers are built tough, you need to ensure the carrier assembly you’re installing it into is up to the task. For heavier vehicles and larger tires, you might be looking at a more heavy-duty axle housing to begin with. The locker itself is strong, but it’s only as strong as the axle shafts and housing around it. Think of your entire drivetrain as a system; the locker is a key component, but it can’t do its job if other parts are weak links.
Then there’s the installation. This is not a beginner’s Saturday afternoon project. Setting up a differential requires precision, special tools, and a good understanding of gear mesh and backlash. A poor installation will lead to premature failure, noisy operation, or a complete breakdown on the trail. I strongly recommend having a professional shop with experience in differential work handle the installation. It’s an investment that pays off in reliability and peace of mind.
Finally, think about the air system itself. The ARB Air Locker needs a dedicated air source, which typically means an ARB air compressor. You’ll need to plan the routing of the air lines carefully, keeping them away from hot exhaust components and potential snags. A well-plumbed system is a reliable system. Taking the time to do this right means your locker will engage and disengage exactly when you need it to, getting you through the tough spots without a second thought.
FAQ
How does an ARB Air Locker actually work?
It’s a pretty clever system. Inside your differential, the ARB Air Locker replaces the standard carrier. When you hit the switch in your cab, it sends compressed air through a small line into the locker itself. This air pressure pushes a clutch mechanism that physically locks the two side gears together. When locked, both wheels are forced to turn at the exact same speed, providing 100% of the available torque to both wheels. This is a true, fully locking differential. When you disengage it, the air is released, and it goes back to acting like an open differential, allowing for normal turning on pavement.
Can I run an ARB Air Locker on the street?
Yes, but you should only ever use it in the unlocked position while driving on paved surfaces. When the locker is engaged on a high-traction surface like asphalt, it prevents the wheels from turning at different speeds during a turn. This puts massive stress on your axles, drivetrain, and tires, and can lead to a broken component or a very unpredictable driving experience. The beauty of the ARB system is its on-demand nature. You only lock it when you need maximum traction off-road, and then you unlock it for the drive home.
What maintenance does an ARB Air Locker require?
The differential itself requires the same maintenance as any other differential: regular fluid changes with the correct grade of gear oil. The unique part is the air system. It’s a good practice to occasionally check for air leaks by listening for hissing sounds with the system pressurized. The air line fittings can sometimes work loose from vibration. Also, make sure your air compressor’s intake filter is clean. Beyond that, they are famously low-maintenance and robust units as long as they are installed correctly and used with the right gear oil.
What happens if my air line gets damaged on the trail?
This is a common concern. If an air line is cut or broken, the locker will simply lose its air pressure and disengage. It will default to acting like an open differential. This means you’ll lose your locking capability, but you won’t be left stranded. You’ll still be able to drive the vehicle, albeit with reduced traction. Many off-roaders carry a small spare section of air line and some spare fittings to make a quick trail-side repair if this happens.
Are ARB Air Lockers reliable?
In my experience and from what I’ve seen in the off-road community, they are considered one of the most reliable locking differential systems available. Their design has been proven over decades of use in some of the most extreme conditions imaginable. The reliability heavily depends on a proper professional installation and using clean, dry air (which the ARB compressor setup provides). When set up right, an ARB Air Locker is a component you can depend on for years of hard use.