Let me take a step back and try dividing the problem into two possible classes --
1) Static - The wheels will point to a greater angle one direction than the other. I think this has been adequately covered above.
2) Dynamic - The truck responds differently to steering inputs one direction than the other. In other words, the truck understeers a lot more in one direction than the other. This could be caused by incorrect camber/caster adjustments if I'm not mistaken.
Of course, it's easy to test which one of these is the problem -- measure the wheel angle at left/right stop while stationary.
Brian
