Other threads have considered the question of using ATF instead of motor oil in engines. Now here's the opposite question: what would happen if motor oil were to be used instead of ATF in an automatic transmission? If you want some assumptions, base your response on 5W20 or 5W30 oil and a late-model transmission (as opposed to an older Ford C6 or GM THM 400). Also assume total replacement with ATF. Finally, would dino oil make a difference vs. synthetic?