[930chef]

i am trying to add fresh swepco to a 1977 turbo trans. i found drain plug easy enough, but what side of trans is filler plug on? i took one plug off and it was spring loaded so i plugged it up, hoping i didnt goof anything up. its been a couple of months since that fiasco i forgot what side i removed. is spring loaded plug the right one or is it other side(passenger or driver?) thanks in advance for expertise.... kevin