For some reason, I'm only spinning the passenger side tire off the line, and sometimes barely spin the driver's side. It's got 4.11 gears & a Detroit True-Trac.

I know the True-Trac's not supposed to do this. The guy that built the rear for me told me to use non-synthetic gear oil with about half a container of that Ford additive. An Eaton rep suggested that I don't use any additive (friction modifier) and while that seemed to fix the problem, there were some pretty strange rubbing/grinding sounds coming from the rear... only when making a slow turn. ie. in a parking lot.

I'm now back to no noise, but one wheel peels.

Any ideas or suggestions? Are these noises normal for a true-trac?