Difference from turbo II differential and N/A differential
 

Hi just wanted to know how to tell the difference from Turbo II differential and N/A. I looking at buying a 1990 Turbo II differential and just want to make sure it LSD. It is out of the car. What is the best way to test it? Thanks

I've never tried it myself, but it's said that if you spin one half shaft/flange the other side should turn the same direction if it's an LSD.

All TII diffs are LSDs, and they use a larger ring gear than the NA diffs (8" vs. 7"). There will be a tag on the drain plug that says something about it being an LSD, and the number of ribs on the case is something like 13. My NA S4 LSD has 11 ribs on the case, and I know the TII diffs have more due to the larger size.

Thanks for your help.

Since you say you've never tried this, I'll jump in and inform you that this is 100% true.