hi

how is the best way to do a backyard transmission flush at home for a ed 6 cyl auto. do you just run fluid through the auto till the oil comes out clean once you dropped the transmission sump then put it back on and fill up?

Its more involved thatn that, takes about 2 hrs to do, and you need a 20lt drum of it, as well as a service kit.
How worn is the rear slip-yoke bush???
Are the servo cover seals/gaskets leaking???
Is the extension housing gasket leaking???
Is the shifter shaft seals leaking???
Is the rear seal leaking???
Is the welsh plug in the slip-yoke sweating/leaking???

There are many things to look for while/before carrying out the service.
Do you have the tools, the time, and the expertise???
If you do it wrong, you could cost yourself the cost of replacing a transmission.