sure is not the wife growling when u get on it? mine does

 

Lift the truck, stick the tranny in park or in gear (manual trans), then spin one wheel. If the other turns in the opposite direction you have an open diff. If it does not turn, or if it turns in the same direction when the tranny is in neutral, you have a limited slip.

 

blew out 3rd gear completeley full rebuild tripple disk and a bunch of other stuff and its on the road!