If it were the shaft seal, it would be throwing a strip of fluid on the underside of the hood. As believer said, clean things THOROUGHLY and then watch it closely to see where it's coming from. If that doesn't work, you can get UV dye to go in the fluid then examine with a black light.
Hope this helps.
'88 300E 5 speed manual, 331K miles
"Change oil hot and change oil often"
“I'd like to know why well-educated idiots keep apologizing for lazy and complaining people who think the world owes them a living.” - John Wayne