Really weird clunking noise in the back...

[happy]

so on my 02 gts long story made short one of my rear pass side 20" I forged wheel was leaking air last summer, so I never really noticed it to much, until I d crank on it id allways feel like the car was trying to twist or something, anyways stripped the gears on the input shaft, I blame the dame wheel, and last day I had it out I was putting it into storage, I noticed a bit of a clunk back in the rear end it seems when I would give it hard n let off, also I took of hard around a corner and only one wheel spun...... never done that before.... what would you guys guess is going on here?? rear end going?? I have acess to another stock rear end in good shape.. my buddy said maby the fluid low or dirty, but not my luck its allways something worse lol

 

[Stonep185]

When was the last time you changed the rear fluid and did you use the non slip additive?

 

[happy]

I never did since I owned it for 5 years now... but also never put many miles on it, whats it call for in the rear end??