Not a really good thing It seems that ARB is having problems with AR12 which is the air lockers for 12 bolt axle it seems that the unit can lock with just one of the side gear/ pinion gears teeth being engaged, putting the full power of the axel look on that one tooth!!! Breaking the tooth off which can then get in between the ring and pinion trashing them, the air looker and most off the time the rear housing. First ARB said this could only happen if the axel was under compression and the locker was open and the window in the locker was faced strait down! So I put a truss on the housing. Still shattered the side gear! Now ARB says that they are redoing gear timing on the spiders|side gears But they don’t know when the new one will be out, and they are not selling the old style, Parts are hard to get now too! I will don’t now what to do for now other than put it back with the new parts that cost more than a new unit, and be nice to it till they get the new ones out in the next year or so!!!!