Yes I agree! If you have angled your pinion on your diff up to eliminate driveshaft angle you have probably messed up your caster angle. Caster essentially is the angle forward or backward in relation to your upper and lower ball joint position. The more positive caster angle or leaned back the angle is, the straighter it will want to drive. The less caster angle or forward lean, the wheels will lose that ability. And negative caster is disasterous. Think of it like a shopping cart. You might have done this before if not try it. You push the cart normally it seems ok. Now run with the cart, hit a bumb or get going fast enough and watch those front wheels. They will shaking back and forth like mad! That is negative caster! So that might be your problem. Or could be a tire/ balance issue!
