What to use to stop tranmission fluid from leaking,when

A deep 904 pan. If you got a link, send it. A Tylenol bottle used to fit perfectly in the seal. Dont know now days. That red plug is bunk: It'll come out as soon as the trans tailshaft drags on the deck. Good advise is to put a skateboard under the tailshaft on its way out so it doesnt drag.