Thanks Dackel
My BMW 1M Coupe uses a GS6-45BZ trans manufactured by ZF.
Redline recommend their D6 ATF in this trans.
http://www.redlineoil.com/product.aspx?pid=115&pcid=7
Discussions surrounding this vs the stock fluid on forums I've searched tend to revolve around cold shifting smoothness and fluid viscosity. From what I've read BMW owners also tend to be utterly petrified about departing from oils that come in BMW bottles.
I simply want to use the best I can buy for this gearbox and don't care who makes it. I am also prepared to wait for the box to warm up before driving spiritedly and I l live in a climate which does not fall below 0*C.
What concerns me about using ATF in a manual trans is it's anti-wear add pack. I don't want 'smooth shifting and good synchronizer performance' while sacrificing wear of gear sliding surfaces and shaft bearings. Clearly I need a mixture of these characteristics, I want the box to last, and was leaning towards using Redline MTL until I used their vehicle configurator tool and read some forums where either stock BMW or Redline ATF D4 is the majority.
From Redline's manual trans lubes PDF found here
http://www.redlineoil.com/content/fi...%2010-13-1.pdf
Quote:
"D4 ATF and High-Temp ATF provides the gear protection of a GL-4 gear oil in an automatic transmission fluid, which is far superior to a conventional ATF. This gear protection makes it perfect for lubricating automatic transaxles and high-performance automatic transmissions. The D4 ATF provides the best low-temperature shiftability. MTL® provides better wear protection in most manual transmissions which call for an ATF which can be very important in racing applications. MTL ® provides the low-temperature properties equivalent to a petroleum ATF. All Red Line transmission lubricants provide excellent synchronizer compatibility"
Seems they're saying MTL provides better wear protection than their ATF oils.