Which gear oil: Redline MTL or Redline D4 ATF ?

[greer]

Hi Guys,

Which gear oil is best for smooth shifting in the M5, Redline MTL or Redline D4 ATF?

Is there another choice that is better?

Thanks,

Greer.

[lincoln30]

I've heard, don't know if it's true, that Redline has something in it that might damage the BMW 6 speed used on the M5 and M3. I ran MTL in my M3 5-speed for years with no ill effects but decided on Royal Purple instead of Redline b/c of these rumors.
You are only young once, but you can stay immature indefinitely! - Ogden Nash

[Stan]

[greer]

Mike Miller of Tech Talk in Roundel magazine swears by Redline MTL. I've heard that's it's bad for the 6 speed M5.

What is your source material that says Redline MTL is not safe for the M5?

[lincoln30]

It was a long time ago, but it was an ongoing topic on M5board.com. It was enough to make me concerned and not use it, after having great luck with it on my other cars and lots of respect for the Redline product and brand.
You are only young once, but you can stay immature indefinitely! - Ogden Nash

[mottati]

same guy to raise the question of it's safety has disassembled some gearboxes and found the m5's box is different than the toyota box that did have issues with redline, so it should be fine.
Mike

[BigGuy]

What is the stock gear oil used by BMW? I looked in my owner's manual, and it simply says "lifetime fluid." I have not had a chance to call my dealer yet. They almost surely won't have it in stock because around here, most customers don't do do maintenance like change fluids. When I ordered manual trans oil at the Volvo dealer for my wife's V70, the parts guy said no one had ever ordered any of that stuff before. Odd...