Just goes to show--If it aint broke, dont fix it.

Transmissions get really really hot!! After draining the fluid a few
times , like you have( do it once more for good luck) a drive through the
city, in some prime stop and go traffic, may just boil the rest out. I
would recheck the level every few minutes to replace the coolant that
boils out.I guess it will steam out through the dip stick tube.You might
find out exactly how much coolant was in the trans that way.The
strainer/filter wont catch any coolant.It is just a fine sive.Thats what I
would do. That, and cross my fingers.