THE REQUIREMENT:
A common misconception suggests that a 4x4 and traction go hand in hand… you can’t have one without the other. The truth, however, is that most 4x4 vehicles send power to the wheels with the least amount of traction once difficult terrain is encountered. The problem is simple – when one (or more) of your vehicle’s wheels loses traction, your highway minded factory differential directs all of your vehicle’s power to those spinning wheels. On road, the standard "open" differential allows each of your wheels to turn independently thus eliminating any binding during turns. Off road, this becomes a major burden as engine power will take the path of least resistance, which occurs at the wheels with little or no traction.
Newer vehicles with limited slip differentials (LSDs), positraction etc may offer some improvement over standard differentials, but more often you’ll find the slipping is not "limited" enough to maintain forward progress. Automatic locking differentials also have their disadvantages. Aside from being noisy, automatic locking differentials often upset the on highway and off road driving characteristics of your 4x4. During normal driving conditions, vehicle responsiveness becomes less predictable, and when highway surfaces become wet or icy, the driver must use extreme caution just to keep the truck in control.
THE SOLUTION:
ARB has been challenging conventional thinking on off road equipment designs for over 30 years, and the ARB Air Locker has been a success from the very beginning. Created to provide 100% traction on demand, without sacrificing any of your vehicle’s highway driving performance, ARB Air Lockers employ a 12 volt air compressor designed to activate (and deactivate) a solid and durable locking mechanism inside the differential. This gives you the traction you need, when you need it, all at the flick of a switch, all within the safety and comfort of the driver’s seat.
The advantage of the ARB Air Locker lies in the pneumatically operated locking system inside the differential. When activated, the Air Locker prevents the differential gears from rotating and therefore prevents the axle shafts from turning independently of each other. With both wheels tied directly to the rotation of the ring gear the vehicle maintains maximum possible traction at all times. When unlocked, it operates just like conventional "open" differentials.
In addition to providing outright improvements to a 4x4’s off road capabilities, the Air Locker offers significant environmental benefits. When approaching difficult terrain, less reliance is put on momentum. An Air Locker equipped truck can be driven in a slower, safer and more controlled manner as a result of vastly improved traction. This style of driving greatly reduces the likelihood of incurring vehicle damage and lessens the environmental impact as well.

ARB Air Locker’s patented design has proved extremely reliable, even under the most arduous conditions. The Air Locker’s strength comes via structural components manufactured from aerospace grades of high alloy steels. ARB engineers increase the number of differential pinion gears, where possible, to distribute torque loads evenly, thus adding to the overall strength of the differential. Many recent Air Locker designs utilize timed gear sets, which further improve strength. This latest introduction to our design and manufacturing process has led to the acquisition of a second US patent on the product.
The design process of an Air Locker involves countless hours of testing. Computerized Finite Element Analysis (FEA) allows the designer to subject each Air Locker design to 'virtual' off road driving stress simulations much more extreme than those experienced in real life.
Destructive laboratory testing is carried out on prototypes to ensure the strength of the Air Locker exceeds that of the axles or other driveline components. Environmental test cells subject prototype models to high temperature running conditions (120°C), low temperature running conditions (-24°C), and harsh wheelspin engagement, for cycle durations of more than 20,000 actuations. Finally, field-testing is carried out with units being fitted to test 4WDs - from Jeep Wranglers to Toyota LandCruisers - operating in the harshest environments imaginable.
Once this exhaustive design phase is complete, Air Lockers are manufactured in Australia by ARB, and sold throughout the world.