I've got the same tranny in my 530i. Here's some info to get started.

http://www.bmwe34.net/e34main/Mainte...0Autotrans.pdf

http://www.ssfs.si/4letnik/Mehanski_pogoni/katalog.pdf

Don't forget to change the FILTER also. I also changed the gasket and needed about 4-5 quarts through the whole process.

Fluid standards are listed in the material. You will need to find something comparable at you local store or order from BAVAUTO or BMA, etc.

I would still like to do a complete fluid flush someday. Don't know if I could do it myself...and don't really want to pay for it. Buying all the fluid necessary would cost enough. I think 11-12 quarts total.