I've tried doing some research, but never got a definite answer on which transmission fluid to use. I am guessing for the SMG transmission, we should be using Manual Transmission Fluid. The only one I found where someone used it on their E60 M5 SMG was the Redline MTF. Are there any other brands you guys suggest? Thanks!

 

It's a manual transmission with electronic/hydraulic controls. I use RedLine MTL, but I'm sure there are many others that will work fine. The SMG hydraulic fluid is CHF-11S, I believe. It should be flushed too. Might as well use the same interval (I do it every 50k).

 

ok thanks! I found this, do you know if this would work? http://www.redlineoil.com/product.aspx?pid=45&pcid=7 I am not sure what the 70W80 GL-4 Gear Oil means or if it's right for my car :\

 

Yes, that's the stuff I use. They also make a 75W90 oil that I use for the differential. For a limited-slip diff, you need a different oil, but our diffs are open. They don't care.

 

Thanks Wolrab!, I was planning on changing the differential oil also, I'll probably get the 75W90 as you recommended

 

Take a look around this web page. I think you will find the answer there.
The CTSC - ZF Parts

 

I saw that page, but notice it said "This oil change kit is for 8 Cylinder,12 cylinder and diesel applications with 6 speed automatic transmission." For the Transmission Fluid compatible for the 545i. Is this the same one for the one for the SMG transmission? And is this transmission fluid better than the Redline one? Thanks.

 

My thought was that you would identify your transmission's type number? They don't mention SMG specifically and I don't even know if your SMG was made by ZF(?). Let us know what you come up with. Thanks.

 

The SMG is a manual transmission. Nothing related to automatics applies to an SMG.