So I have taken it into my sparsely furnished wits that I should drain about three quarts of atf even though my trans is without complaint or symptom. I have been made aware that my drain pan does not have a drain plug so I decided it would be easier to just disconnect the upper trans cooler line, attach a hose at the appropriate point and let the front pump work its' magic. The question then becomes this: Is the atf going to pump out the radiator side or the line side ? I'm leaning toward the radiator side because were I the designer of the system I would have the fluid pumped into the bottom of the cooler to preclude air entering the system but I've been wrong once before. Any of you guys done this before ?