After reading Mark Kovalsky's article on how to change the atf in a 4R100 trans, I've got some questions.

On step #5, you place the clear tubing on the return line of the transmission, and run the engine, pumping out the old atf, and you shut the engine off when you see air coming through. You refill the same amount you pumped out.

Here's where the question is, it says to repeat step #5. Does this mean repeat the whole thing, or just re-fill until you get 19 quarts in the trans??

I'm still trying to figure out what the heck is going on in the transmission with the air. . .I'm assuming since in steps before #5 you've drained the pan, and added the same amount of fluid drained, air has entered the trans, and that air will be pumped through the trans, through the torque coverter, through the lines to the cooler, out the lines, and down the clear tubing. So...the old atf will be pushed out of the trans, tc, trans cooler, because the air is pushing it out???

So now since we've expelled all the old atf, we fill with the same amount removed. . .and then do the air thing again?? This is where I'm getting confused! I can understand purging the system once more, but say you've done this twice. . .wouldn't the trans be full of new fluid, and only be pumping new aft through the system eliminating the need to watch for air through the tube because all thats going to come out is new atf? Couldn't you just connect the cooler line back to the trans, and fill?

Sorry for the crazy questions, but I HATE reading a set of instructions and not being able to be sure of what exactly I'm doing.