[78w72]

Hope you can confirm where its coming from, smoke test is a good idea but at this point if you have wiped it all dry around the leak then went for a drive & saw where its wet only on the rear of the pan & not up by the filter housing, filter itself or valve covers etc... i think youve found the source of the leak.

Im pretty sure the rubber U seal isnt supposed to have RTV on it, just the corners, unless the bop gasket is designed different, those early 3 hole pans/gaskets are known to heave problems sealing, the later 5 hole design is better but still not as good as the cork gasket around the main cap.