So, my 2007 9-3 6-speed manual came with the MU9 gearset F40. Itwas originally filled with GM 88862472 gear oil (Castrol Burmah, BOT 0063, 75W-85 GL-4). About 2.5 years ago, I drained and filled with RedLine (50204) SAE 75W80 API GL-4. The consensus then around here was that the RedLine handled cold shifting better and reduced the 'notchy' feel. I personally didn't notice much change of the notchy feel, but it does shift better when cold.
in about 2009 GM released an improved fluid for the F40, GM 93165290 (BOT 402) but from what I can tell this was done specifically for newer F40 transmissions (MR6, MK6, etc). It is still a GL-4 oil, meaning it's compatible with the original fluid in my MU9 (and by extension the RedLine fluid).
Now that I've been messing with my transmission shifing slop and becoming over-aware of sounds my trans is making, I wonder if the RedLine is the best I can be using. I've noticed a but of a whine in 3rd gear in very limited conditions such as light throttle level driving. Hard throttle or coasting it goes away. My trans fluid is still clean and transparent red-ish, so I don't believe there's any damage happening.
Would it be worth changing over to the newer 93165290 fluid for future longevity? I assume they superseded the old fluid for a reason. Or am I over-thinking all this? I just want to take care of my car the best I can. Thanks,
in about 2009 GM released an improved fluid for the F40, GM 93165290 (BOT 402) but from what I can tell this was done specifically for newer F40 transmissions (MR6, MK6, etc). It is still a GL-4 oil, meaning it's compatible with the original fluid in my MU9 (and by extension the RedLine fluid).
Now that I've been messing with my transmission shifing slop and becoming over-aware of sounds my trans is making, I wonder if the RedLine is the best I can be using. I've noticed a but of a whine in 3rd gear in very limited conditions such as light throttle level driving. Hard throttle or coasting it goes away. My trans fluid is still clean and transparent red-ish, so I don't believe there's any damage happening.
Would it be worth changing over to the newer 93165290 fluid for future longevity? I assume they superseded the old fluid for a reason. Or am I over-thinking all this? I just want to take care of my car the best I can. Thanks,