I have an oil leak coming from the auto transmission just above the oil pan gask on 1994 Mercedes-Benz C280

on the right hand side of the auto transmission there is a round cover that moves in and out when I push on do I change this cover seal that is leaking.It looks like its held in with a circlip.

Asked by for the 1994 Mercedes-Benz C280
ck fluid level to start with. it maybe over full