While most people know that there is an ARB Air Locker available for the Samurai/Sierra models, it is not widely known that ARB also makes air-actuated lockers for the Sidekick/Tracker and Grand Vitara models. After I realized this, it still took some pondering for me to realize that I could add this locker to the Sidekick rear differential of the Spidertrax Full Floater installed in my Samurai. If there is a 'Kick, Tracker, Vitara, or Grand Vitara in the family longing for true four wheel drive, an ARB Air Locker is the ultimate in locking differentials.

Why bother with an air locker?

The full floating rear axle on my Samurai came from Spidertrax with a Detroit EZ Locker. On the trail, this locker was the best single modification any 4-wheeler could ask for, but the on-road performance of the locker was less than desirable for me. While the on-highway quirkiness was tolerable, the around town handling and drive line wind-up of the auto locker was just plain unacceptable, in my opinion.

In a mid-sized or full sized truck with an automatic transmission, I'm sure that the locker would have almost undetectable. But with my Zuk sporting 33 inch tires, 4.63 differential gears and the 4.89 GRS II transfer case gears I was getting a lot of drive line wind-up. A locker adds to this wind-up with an addition of a maximum of a quarter-turn of the pinion required for engagement. It is that little quarter pinion-turn that was really making me crazy. Daily driving in and out of parking lots with this wind-up and locker engagement caused what I have been calling "drive line slap-back", It occurs when the wind-up in the drive line is suddenly released with the disengaging of the clutch causing a loud bang from inside the differential.

As un-nerving as it was, I was more concerned with the longevity of my drive line with all the on-road use it had been getting lately. I was about to return to an open diff--that is until the idea of an ARB Air Locker was put before me.

Reading up on the Air Locker, I found myself more and more impressed. The ARB Air Locker, which has been in production for more that 15 years and exported to more than 50 countries, requires no more maintenance than a standard differential. But what sold me was one of ARB's sales pitches that states that, "the Air Locker does not have any adverse effects on tires, transmissions or handling in highway operations, unlike automatic and limited slip differentials."

Getting the project started

To purchase the Air Locker, I began surfing the net price shopping for ARB lockers. By far, the cheapest price for Suzuki Samurai and Tracker/Sidekick ARBs came from Rocky Road Outfitters in Utah. Also needed for the Air Locker is an air source. ARB recommends using their ARB Air Compressor (also available online through Rocky Road) which is an under the hood mounted compressor and reservoir tank. Already installed in my Zuk was Wheeler Off-Road's GenII air compressor and tank. Not wanting to waste space or money on an extra compressor, I decided to mate the ARB to work with the existing air system.

The Wheeler Off-Road five gallon air tank (which nestles under the passenger seat floor pan, encased by the nerf bar) holds air at 120 psi. The ARB Air Locker works between 50 and 85 psi. To reduce to proper operating pressure, a regulator was plumbed in between the tank and the Air Locker actuating switch. This will ensure that the 120 psi in the tank will not blow the rubber seals in the locker. Be sure to get a regulator that regulates pressure and not just volume.

Its really a quick & easy installation

Do not be scared off by the instructions that say only a reputable auto shop should put in your ARB Air Locker. Chances are, the mechanics at the nearest shop in town have never seen an Air Locker themselves. But with that said, the only skills needed to put in the ARB in a Samurai, Sidekick or Vitara is previous experience with changing the differential bearings or in doing a ring and pinion swap. To put it more simply, if you have ever done any work on a differential before, chances are the ARB installation will be a piece of cake. For this swap, it is also helpful knowing how to tap threads; a task which must be done to install the air line. What makes the installation difficult for many, though, is ARB's one page installation manual. For additional information we suggest also referring to our installation article.

Performance impressions

The selling point of the ARB for a Zuk that already has an auto locker like the Detroit or the LockRight is that the vehicle gains back the 'street friendliness' of an open differential without losing the advantage of a locking rear end. I got exactly that with this installation. The unlocked Air Locker in the rear differential behaves no differently on the road than the stock differential. On the trail, the locked Air Locker behaves like a welded (spooled) rear end; there is no individual tire slippage whatsoever. So thrilled am I with the ability to turn the locker on and off with the push of a button that as soon as the Samurai's 'slush fund' is replenished, another ARB will find its home in my front differential.

--Adam Leach