Help on Tranny Fluid
 

According here: http://www.xoutpost.com/articles/x5/e...nce-guide.html Redline ATF Dexron III D4 ATF is for manual tranmission. Will it be bad if i use the same fluid on my steptronic tranmission? Please help, coz im not sure if i should use this since this is what i used on my E46, and i still have new unopened bottles. Please help....thanks!

umm that sounds right. ATF stands for auto trans fluid i thought. maybe I am wrong, but I am pretty sure thats what stealership added when they dropped my trans to perform the tsb.

exactly, thats why i am confused, it states ATF (Automatic Trasmission Fluid) and yet, its for manual Tranny? Any more help is appreciated.

I think its all the same. Both my Z's are/were 5 speed and i could have sworn it took ATF too.

Lots of manual transmissions take atf they use it because it is thinner and less friction so you get better gas mileage

yes. lots of manual boxes use ATF.

so am i safe using this on my X5 step? Wondering why the guideline did not recommend that?

Auto trannies tend to heat up a lot more, so thinner fluid may not be a great idea.

Some people use the redline ATF but the actual spec for manual transmissions is either bmw MTF LT1 or LT2, depending on the year. But that is not really easy to acquire, and isn't cheap. I used RP MTF in mine.

I believe RP synchromesh is an acceptable substitute for the ATF, but there is a lot of conjecture and theory on this all over the internet, as far as the MTF goes.

I would not be so quick to assume acceptability. Some transmissions do spec ATF, but some spec 10w30 and still others call for other things. Heat is the biggest factor in automatics, and it is not nearly as big of an issue in manuals, where thinner lubricants would be acceptable.