I have been getting some really bad vibes coming from my shaft, and need to figure out how to correct them asap. What I've gathered so far is that I need to shim my rear diff, but how do I find out what degree shims to use? Everything (driveshaft, axles) is stock exept a 4" lift with blocks in the rear and 35's. Going to a 4 wheel drive shop or a driveline shop is out of the question being that I'm stationed in Germany right now. Any help is greatly appreciated.