RE: Differencial
I dont know if this is your problem or not, but I've read about Diffs needing "spacers", right from the factory, to make them more efficient and reduce friction? (Basically the gears dont fit properly, so ya need to add or remove spacers to get the gears properly alligned and working smoothly.) Also, some good silicone diff oil might help? Try something thinner than you've been using, to make the diff slip a little more.. (Note: This is all from stuff I've read.. I've not built or tinkered with a gear diff for over 8 years..) So make sure and do some forum "searches" on "differential setup" or "diff rebuild" or something similar, and see if you can find some step by step directions to get ya fixed up!! Good luck!!