I jacked up the rear end in neutral, spun drivers wheel and the passenger wheel spun in opposite direction, so I'm pretty sure its an open Diff.
Thing is, when I spun the passenger wheel, the drivers wheel didn't spin at all.
Is this normal? Or a sign of a wearing out Differential?

 

Did the driveshaft turn instead?

The wheels on the rear axle are mechanically linked, if you turn one, and something else doesn't turn, either the other wheel, or the driveshaft, you need to pull the cover, and see what things look like inside.

 

Thanks! I will have to re check, I cant remeber if the shaft turned. I was just trying to determine if I had limited slip for a fluid change.
As for taking the cover off and taking a look, I not sure I would know what to look for.
So if the shaft turns, but not the other wheel , you think that is ok?

 

Yeah, so long as one or the other turns, you are good.

Anything possible damage inside the diff will be patently obvious once you have the cover off. Likely chunks laying in the bottom of the pig, and other expensive looking things.

 

Ok, so I see the driveshaft is spinning when both wheels turn. Also, noticed that rotating each wheel in reverse causes the opposing side to rotate opposite direction, but spinning each wheel in forward direction doesn't.
Thanks again!