For those with F450 and the 6.4 diesel engine. What kind of fuel mileage are you getting. My truck is a 4x4 flatbed and auto tranny and is only getting 7.4 MPG. Seems kind of low to me, The truck only has 800 miles on it, but I am thinking it needs to go back to the dealer for a checkup. I already know somebody will have something smart to say about it should of been a duramax. Well I traded a 4500 Dmax in with 14,000 miles for this ford so dont even get me started.