1965 Dodge Dart Charger

The oil pan for the transmission was not even close to be restored so I found an NOS one from Brad's. The pan is laser sharp but have some small surface rust. After cleaning the pan I found out that the oil pans were coated in cosmoline. I thought that Chrysler started using cosmoline in 1967 for the lower control arm so this was news to me!

Does anyone have any input in how this was applayed on the oil pan. Sprayed or dippped?