First, I have not opened my diff yet to even verify I have a Z31 LSD but it is a 3.70:1 and it does have the finned cover. I bought the car with it installed and I know one of the previous owners did install one.
When I jack up the back and spin one of the wheels, the other one does not move at all. After reading some older posts, I should have checked turning the driveshaft too but I didn't do that test yet.
Is this a normal symptom of the clutches going bad? If they are bad, will I get any use out of the LSD or is it just an open diff now. I skimmed through the shimming thread but I'll have to go back and read it again to fully understand whats going on.
Also, if the fluids were changed but no LSD additive was added, would this cause any problems?