I'd give some thought to awspence's post. I put a lockrite in a rear D35 years ago and broke it the first trail ride, granted it was Guardrail at Tellico 
Seen several other similar incidents also. Considering how awspence does on the trails I'd consider his advice. LOTS of times I see rigs with the front end over the obsticle, locker in the rear and both rears turning but not getting up. With both fronts turning and pulling instead of pushing from the rear it might make a difference. Either way, a locker is going to help your traction no matter which end you put it in
