Ours was leaking oil as well. Initially thought it was the upper oil pan gasket. Turns out it was a clogged CCV filter. Ford published a bulletin on it.
https://static.nhtsa.gov/odi/tsbs/20...60870-0001.pdf
Had trouble finding a shop that could get us in so I ordered one from a dealer off eBay and did it myself. Fortunately I caught it early so it didn't blow any seals or gaskets.
Not a bad job at all. Dry as Quartzite under there now.
Cummins has a filter too. Things can get really ugly if they get clogged.