Gladly,

The primary problems with ARBs, are:

1. Many points of failure
2. Difficult install
3. User intervention required
4. User maintenance required.

More on this.

Item #1

The ARB requires that you have a proper installation, it requires airtight sealing connections, it requires 12v of power, and it requires a minimum of 80psi in low volumes to remain engaged. A failed airline, air fitting, o-ring, compressor, relay, fuse, switch, or faulty wire, can render them inoperative.

Item #2

Installing an ARB is considered the most difficult by most shops (its not, but it is the hardest common install). The failure to excercise due care can mean the system may not work once installed, or may fail shortly after install. The biggest problem is the installer pinching of nicking the o-ring on the carrier which cause premature failure.

Item #3

Locking the Diff requires the user to switch the unit on and off. Not normally a problem, but can become a problem if the unit doesn't unlike when you want it to. Common issue here is to be in the middle of a tough climb, with the front locked, need to change lines, and switch off the front locker switch. Locker doesn't disengage because of driveline wind-up. So you have to back off your climb 3-6 feet, pick the new line, re-engage the locker, and try again.

Item #4

The ARB locker needs to be engaged at least once per month to keep the o-ring lubricated. failure to do this will allow it to become dry and brittle and not hold air. I had to winch one poor bastard for HOURS in Atlanta 2 years ago when his dual ARB equipped truck had both o-rings fail. He was on basically in an open diff truck with a foot and a half of mud keeping him from getting traction. He mentioned he had last engaged his lockers about 6 months prior in Tellico. His was not the only ARB failure that weekend.

-P