do you guys who have done a tranny flush do you use only the audi atf or can you use like royal purple?

 

Audis can be very picky. Stick with OEM.

 

I just had my indi flush my transmission. 97 A6 with 138K. He recommends that you only use the OEM fluids.

 

Our transmissions are used in many many other cars. http://en.wikipedia.org/wiki/ZF_5HP19_transmission There are is more fluid interchangeability then people would lead you to believe. Do a google search for 5hp19 http://www.google.com/search?hl=en&q...=Google+Search
Most of the results are from BMW owners who have the same question as you do. I personally have generic esso synthetic fluid in mine.