I've had the same running problem for the year and a half I've owned my Edge. The seal was replaced twice and still leaked. After the second seal was installed and leaked Ford instructed the dealer to replace the PTU. The was fine for awhile and then the seal leaked again. It was replaced again and I sitll get the smell ocassionally. This is either a major design flaw by Ford of the dealer is incorrectly installing the replacement seals. Very frustrating.