Hello folks, just bought my son a 2007 2500 4x4 and have just a few questions regards it. Probaly wasn't the smartest thing to do right now with the gas prices, but oh well. It is a nice truck, and the price was good. I, too want to squeeze all the MPG out of it I can. It has Nitto 37x13.5 50R18's on it and the speedo has not be recalculated. The overhead says 8 mpg, but from reading other post it may be off a few MPG. The gears, I am pretty sure are 3.73 as I can't find any tags to say otherwise. It is also an automatic. I may be looking at a programmer soon, but being new to diesels not really sure what to look for. Not really interested in max performance, because my son is driving it. Any help would be great. I know I probably left out alot of important info. Thanks for any help.