I've done some research and the general consensus seems that regardless of whether or not I have an LSD on my 93 325is, I should still use the Redline 75x90 gear oil with the LSD additive as it is superior, than the oil that doesn't have it. I'm I correct in this?
I'm doing the 100k Inspection II service about 8k miles early because I'm hearing some differential noise when I drive in reverse while turning. It's a weird low rumble, almost like my tire is slowing rubbing inside the wheel well. The noise dissipates after I drive for a few minutes. I've read that people with the same problem have solved the problem by adding the gear oil with LSD additive.
The differential was actually replaced due to the same noise at about 40k miles - I believe this was kind of jumping the gun, and I wonder if all they needed to do was add the gear oil with LSD additive.
What do y'all think?