I have noticed that when there is ice on the ground and I have one wheel on the ice and one on dry pavement only the one on the ice spins and I go nowhere. I would think that is wrong and it should be trying to put the power to the wheel with traction instead of spinning the wheel on ice. I got stuck one day just because I had one wheel on ice and the front wheels against a curb. I was soooooo pissed off.

 

Well it would sound right to have the wheel with the least resistance willing to spin more than the one with the most resistance. Since our cars are limited slip I beleive that means it allows one wheel to spin at a different speed than the other to make things a little easier while turning and such. But the posi locks in both tires apon hard acceleration off the line. It does sound kinda wierd to have only one of yours spin, I would think both should. But in your situation I somehow think it sounds normal. I'd atleast get it checked out. The backyard method would be to hit some back road and try to do a burnout. See if both tires turn equally. If they do you probably don't have a problem. If they don't, then obviously you do. Good luck.

 

think your posi has worn away into an open differential
that'll cause it to spin only one wheel at any time i believe