Blue92 said:
Thanks Elmo. I'll let you know when I find out. Oh BTW. how would I know if it is the rear diff? How do I check? Since I've got alot of time on my hands and another car to drive, I think I'd like to do it myself. Any suggestions? ... Ok.. well I just read the rest of the posts. I think i'll have it towed to Brian @ GTPro.
Or I could take everything apart and bring the parts to him.

heheh.
this is not to bad actually... take your 2.5 ton Floor jack... (you do have one, right?) and lift the car from the rear differential (entry point from behind the car, as long as you don't have the car lowered, you don't have to prejack the car from one side, or roll the rear wheels up on 2x6's...) After jacking, put the car in first gear. This will prevent the car from rolling. additional jackstands under the side frame jacking points forawrd of the rear wheel wells for safety is not a bad idea either.
Once it's up, carefully remove the four bolt/nut combos off the rear of the driveshaft, and pop the end of the driveshaft off the rear diff pinion flange. Tie the shaft up and away from the area (use one of the forward rear carrier bolt mounts to tie it up) and Try rotating the flange by hand. With the Ebrake off (you did remember to take it off after you put the car in gear, right?

) there shouldn't be alot of resistance to turning it, probably about 5 lbs of force or less. Plus, there should be little to no play. Obviously, any crunching or grinding noises is BAD.

Then, have a friend rotate one wheel, while another friend holds one wheel It should be stiff for them to turn, but the rear Viscous coupler should allow the one wheel to turn the flange. Same for the other side. If only one wheel is rotated, and the other is not held, they should both move in the same direction, and the flange should turn rather quickly. (The benefits of a Limited Slip Diff, thanks to the Rear Viscous Coupler.

)
Start with that, and let us know what you find. If it all looks good from there back, we'll move forward and see what else we can discern.
Elton