There is some bad advice in that link and thread, do not use ATF or 75w90 oil in your transmission as some in that thread recommend. I use Red Line D4ATF (this is not the same as plain ATF) is my differential and 75W90 in the transmission. I got this information for my roadster directly from Red Line :"Thank you for contacting Red Line Oil, in your M Roadster I would recommend the 10W40 in the engine, the D4ATF in the manual transmission and 75W90 in the differential. " Do not use 0w40 motor oil either. During your winter months, assuming you drive the car in the winter use a 5w40, other wise stick to 10w40, and for motor oil I use Mobil 1.