So I went out wheelin last night, in the snow, and I was backing up(the first time)when I heard a "click,click" noise. I thought it was coming from the front but my buddies said that they saw both wheels(in back) spinning when one didn't have grip and the other did. I usually don't trust until I find out for myself. So does this qualify for being limited slip? The "tech" at the dealer said that some come stock with posi and others didn't. Any thoughts? Thanks!