I tried searching the forums but did not find an answer. I have a 2009 Chevy Cobalt base model with manual transmission that I recently bought that has more than 140,000 miles on it, and I'm aware that these aren't supposed to have transmission fluid changes but with that kind of mileage I believe it's about due. I'm trying to find out what type of transmission fluids are compatible with these transmissions? I believe I recall my owners manual showing 75W85 gear oil, The closest I've been able to find at auto parts stores is 75W90. Would that be as good to use, or is it a bad idea?