[wolfe]

Did a bit more digging on that subject today, and from what I found it sounds like the ATF is great for syncros, but is perhaps not so good for the bearings - especially at high temperatures.

I also read what JHZR2 is saying too, that the additive package is weaker in ATF than manual transmission fluids.

I'm tempted to try the MTL now, I have enough left over so that I can change it two or three times and get any residual ATF out of there. Then, if I don't like it when it's cold I'll probably go back to the BMW fluid and chalk this one up to experience.

Seems like good shifter feel doesn't necessarily mean it's best for the transmission.

Some more information, gathered from oil analysis reports and product info. I'm not drawing any conclusions from this as it's beyond my understanding, but figured I'd share the information I found:

The viscosity of the BMW MT-LTF-3 is apparently around 6.1 cs @ 100 degrees. Redline's MTL is 10.6, and the D4 ATF is 7.5.

So I'm guessing that's at least partly what redline means by they recommend something closer to the factory baseline. The MTL is a good bit thicker than what comes in the car from the factory.

reportedly taken from a bmw operating fluids manual, in 2005:
MT-LTF-3 seems to be thinner than MT-LTF-2. Apparently 'all cars with a manual transmission and n52 engine got MT-LTF-3'.