[RPM Frank]

That usually doesnt happen, check the support bushings on the front diff and replace if needed, sounds like your alignment problem might be there, most people dont even know they are there. The best bet for staying with leafs is what I outlined earlier. If your getting any real power to the ground stay away from lowering blocks and get a set of Cal-Tracs for traction. The 4L60E is a great trans but you'll need a computer for it. Start with a 700R4, no controller and we build them to handle up 900lbs torque. I found the best combo for the front is to use the factory ZR2 torsion bars, they have the rating and made a huge difference. I tried a coilover arrangement on one truck but had some major interference problems when turning deep.