Twin-Spin Axle Options
This isn't the first time we've brought you this Locker Lowdown story. But like chocolate ice cream, cold beer in the summertime, and Catherine Bach in a pair of Daisy Dukes, some things just bear repeating. This is Jp's all-encompassing collection of traction aiding reviews. We're speaking factually here, not just barfing back some catchy phrases from a manufacturer's marketing brochure. And while you may not find absolutely every traction aiding device ever manufactured listed here, you will get the true skinny from a team of Jeep huckers who normally test stuff to the limits. We've wheeled 'em, commuted with 'em, and sometimes broken 'em. So read on for the truth.
ARB Air Locker
Overview: An ARB Air Locker operates as a normal open differential when not engaged. When engaged, a collar is pneumatically moved to lock the spider gears, creating a spool. When locked, both axleshafts turn at the same rate, whether in a front or rear application.
If you like the way your open diff behaves on the street, then an ARB is for you; it goes unnoticed. Or you can lock it up and chirp tires when parking to impress the ladies.
As long as you feed it the required air pressure, the ARB locks and unlocks crisply and predictably off-road. We haven't had any need to jockey the vehicle around to get gears and pins to line up. It's on when the button is on and off when the button is off. When engaged, both wheels spin at the same rate, but offer the flexibility of being turned off for super-tight turning. Makes a great front differential for twisty trails.
Good: Highly versatile, delivering excellent balance between on- and off-road requirements. Differential is very strong and can take the shock of an axleshaft snapping under load without failing.
Bad: One of the most expensive lockers out there per application. The air lines can be vulnerable to obstacles. Requires a source of onboard air. Lots of things that can go wrong if not installed properly. We've suffered a few internal seal leaks either from high mileage or contaminated oil. The result is gear oil traveling up the air line and out the solenoid purge orifice. On two of our units, air leaks from the seals kept the unit from locking.
Rubicon TJ TFS Air Locker
Overview: The good news is that if you bought an '03-'06 Wrangler Rubicon, you got a pair of these for free. The Rubicon's pneumatically-operated TFS lockers featured an open/spool configuration in the front and a gear-driven limited slip/spool configuration in the rear.
See Truetrac listing for more information.
The units are unintrusive when unlocked and offer spool-like traction when locked. Aside from very few compressor or air line troubles caused by trail debris, the lockers themselves are extremely durable and most of the time are quick to lock or unlock. Off-road, they've proven themselves for use with tires up to and over 37-inches in diameter with no ill effects.
Good: Long-lived durability, and exceptional off-road performance.
Bad: They're not exactly cheap or very easy to come by unless you're starting with a Rubicon or a set of replacement axle housings. Also, the lockers require a very low-pressure (3-5psi) source of air or you can blow out internal components.
Auburn Limited Slip
Overview: The Auburn Limited Slip uses cone and friction materials to create enough friction to hold the axleshafts together. When enough torque bias is realized between the two shafts, the clutches give and allow differentiation of the shafts. In layman's terms, it grabs until it can't grab anymore, then it turns.
You'll hardly know you've got an Auburn in the rear of your vehicle unless you make enough power to spin the rear tires-then, just look for the two black patches on the pavement. We never experienced chirping or handling quirks when driving it.
Good: The Auburn's excellent street manners and decent traction off-road make it a good choice for daily drivers and mild wheeling vehicles.ter text here.
Bad: Requires gear oil with a friction modifier and some installations require slight modifications to the housing. If you're running 33s or bigger and hit some harder terrain, your off-road performance probably won't be that satisfactory. The unit has wearable parts inside and cannot be rebuilt at home. It must be sent back to the factory for refurbishment, which may be required after 100K miles of normal enthusiast usage.xt here.