Will Ford dealers work on Coach with 6.8-liter V10

Ford truck dealers will, car dealers won't. They don't have the lift equipment or large bays, they don't stock truck-only parts.

This is an issue mostly in metropolitan areas where there are multiple competing dealers and separate truck centers. My experience in rural areas in the middle of the country is that all Ford dealers are truck dealers, all GMC dealers are truck dealers, and most Chevrolet dealers are truck dealers. FCA is still trying to sort out dealer arrangements.