Diffs, lockers, limited slip???

[Burns]

My first question - In a stock 1990, which do I have?

Second - What is each, what does it do, and which is better?

Thank you all.

 

[Yardape]

Stock it could be a limited slip or a conventional (open diff.) Could be either depends on what the original owner purchased. The easiest way to tell is to jack up the back end so both rear tires are of the ground. Put the truck in neutral, turn one tire and watch the other. If the other tire turns the same direction its a limited slip, or posi. If it turns the opposite direction then its an open diff.