Hi hope i can find some help. I have a 82 300td wagon. I had a transmission leak that was pouring out form the pan. So I changed out the gasket and filter and the minute I added fluid it just began running out.
Upon further inspection, and frustration, I tracked the leak to a small hole(opening) which is just above the center pan bolt on the housing, passengers side. using a mirror and flashlight it looks like it is NOT threaded. Might there be some sort of plug that popped out...Myself and a fellow mercedes tinkerer both have no idea what the hole is for. Can anyone help me? It just pours out.

thanks
Marty