What Can Cause Uneven Tire Wear 8 3/4 posi ?

Sure grip senses an imbalance in the 2 axles rotation by the cone and helix system in a cone setup. When one side overruns the other the cone unwinds and puts more pressure on the opposite axle and that usually gets them back In sync. That would prevent a one tire in the bleach box burn out. Clutch sg may work on a different principle but the road crown would be a tough one to justify mechanically. In the fsm they tell you to adjust the ride height when you are seated in the driver seat, perhaps that 200 lbs on the driver side is enough to cause more wear? My trucks fuel tank is on the driver side too and that has a mean lean on it when it's parkes. But I think the frame or the box is bent anyway.