transmission vent location on 2000 Ford Expedition

Where is the transmission vent located? How do you check to see if it is plugged, and what is the likely culprit if it is leaking fluid around the rubber plug that fills the inspection port on the bell housing of the transmission?

Asked by for the 2000 Ford Expedition
1 answer
The main suspects would be the engine rear main seal and the trans input shaft seal. And if you have a hydraulic clutch withe the slave cyl. inside the bell housing the slave also.