egarant,
With that much weight, I don't think you want a front locker at all. The only reason for a front locker is to keep you moving when you get your axles all twisted up and lift a wheel off the ground. You are not going to get your axles all twisted up, or get a wheel off the ground, at least not without loosening the rear tie downs mightily to avoid pulling your camper apart. This is axle twisting: you are not going here:
I'm sorry to hear of a former poster having two broken OX lockers. That's the one I had in mind for the front D60 on Cabeza de Vaca. Oh well, back to the drawing board. I just don't want to spend the $ for another ARB that would have so little value over time. I've had almost every locker ever made and they all have plusses and minuses. Well, except the Trashloc. The time you would need a front locker on a 6 ton rig is miniscule compared to wise trail choices and would only be the 60% effort with a rr LS. Unfortunately for you, a high capy winch is the 100% effort in self-extraction for your TC. Only another completely locked up heavy TC would have the nalls to pull you out of the muck. The big deal is: if you're not sure, don't go there.