Originally Posted by citizen_insane
I'm looking to change out the transmission fluid on my 6-spd E90 328i. I've seen 3 main suggestions: Redline ATF D6 (not D4, I live in Iowa, it gets cold), Redline MTL and OEM Bmw MTF.
I've heard people saying they prefer both the Redline products over OEM, but there doesn't seem to be much of a consensus. I've read NOT to use Royal Purple since the OEM fluid left in the tranny/diff will degrade it after a few months.
ECS tuning recommends the Redline MTL and I'm somewhat inclined to listen to them since I assume they know what they're doing (they've been in business for quite a while).
I'm also planning on using Redline 75w90 for my diff. It matches the spec for the OEM non-LSD fluid from what I've seen.
Anyone want to chime in on what to use?
If you're rejecting D4ATF because you feel it's too thick for your climate, MTL will be even worse as it's thicker. Now, I've used 9cSt fluids like Redline MTL and Amsoil MTF in my E39 in a (southern) Canadian winter with no problems whatsoever so....
Your Amsoil equivalents would be Amsoil MTF and Amsoil 75W90 (SVG) for the rear end. I've used both Amsoil and Redline in BMW drivelines and I've been happy. My E90 has Amsoil in it right now.