[V8] flush transmission

[chris brown]

 Well im going to do this very soon on my 1990 V8 (flush tranny) 
 I spoke with a audi tech and he said he has a 16 quart flush machine and would not recommend pulling the pan and filter that a 16 quart flush is adequate. He told me if i have chips and filings in my pan the tranny is a goner anyhow.  I was wondering what you guys thought of this? 
 The car has 90,000 orig miles and im assuming it is original fluid. I would really like to do it myself because the price he told me was $400.00 out the door with full  synthetic flush and synthetic fluid.   My questions are:
 If i disconnect the transmission line at the radiator and run it all out? Where do i put the new fluid in?
  Do i have to start the car a few times to get the fluid all the way thru the tranny?
  If i repeat this a couple times and then finish with top of the line synthetic fluid wont i be doing basically the same thing he is doing?
 I really dont feel like spending 400.00 on this.   any help will be appreciated.