Mack 675 or 676 Turbo Diesel used Engines wanted

From : mec2002

Q: i just bought a 2005 power wagon 2500. i have only driven it 200 km on the highway now since i got it a few days ago and the computer says i am getting 11.8 mpg. this sounds really bad. my window sticker did not show an epa rating and when i called the dealer they just said that it will get the same as the 1500 with hemi with to me sounds like a quit bullshit answer. anybody else out there driving a 2500 ram with hemi that can tell me what kind of city/hwy gas mileage i can expect i imagine that the gas mileage will increase after break in period of the truck right i am also planning on towing a 5500 lb dry travel trailer across country with it and was hoping for 10 mpg with that but if it is 11.8 mpg with no load i am concerned ! .