But Mad North-Northwest
Join Date: Sep 2003
Location: SF Bay Area, CA
You can use what you want, but the statement "the NS is for clutch type LSDs" is incorrect and further confuses folks about the difference in formulation. People should read the Redline tech bulletin as it clearly explains the differences and tradeoffs between the two fluids.
I've tried a lot of gear oils over the years, myself. My experience is that the Spider diff is pretty indifferent, just use a GL5. I use Swepco 201 GL5 in the Spider gearbox and diff (and the transaxle in my former Milano) and like it better than the Redline 75W90NS, but that's just my take.
1963 Giulia Spider (1750 engine)
Former: 1987 Milano Gold