okay, i got my aluminum diff cases in the mail today. I took the diffs out, dissasembled the diffs, degreased them and then filled them both with 50,000 weight diff fluid. They both roll forward very smooth, but here is the problem (or maybe not, maybe they are all like this): i went to test out the diffs and the new fluid by turing the main drive shaft, and holding one wheel output shaft (just to see how locked up the new fluid makes it). And it seemed to turn fine for about 3/4 of a rotation at the other side of the output cup, and then it seemed to feel like it kinked or jammed up. Well i kept on turning in past the slight kink that i felt and sure enough it would do it in the same spot every time. So i took the diff back apart and inspected and cleaned and did everything again, and it does the same thing! What the heck, has any one ever felt there diff not feeling so smooth as they hold one wheel and turn the drive shaft? The other diff seems fine, and like i said it rolls forward fine. And when you hold the brakes, and turn one wheel, the other wheel spins in the other direction smoothly. What gives guys?