Diesel Gas mileage ?

Does anybody know what the gas mileage should be for the following vehicle?

03/04, 3500
4x4, crew cab
short bed, SRW
automatic, 3:? gears

Even a close answer would be good and let's assume we are just driving down the highway empty.

Then what would the estimate be for a 13K trailer on flat and hills?

Thanks

i would say about 16 just driving around and 10-12 loaded.

i would say about 16 just driving around and 10-12 loaded.

My '00 Cummins gets 16-17 in town, 19-20 on the highway unloaded and I've never seen worse than 12 (towing 7,000 lbs. in town). My truck is an A/T 4x4 with the 3.55 (or is it 3.73? not 4.10 either way). One thing to remember is that the diesel doesn't break in until at least 20-25k miles. Check on www.turbodieselregister.com for answers from people who have the exact same setup.