Welcome to the diesel crowd! You will love your new Duramax diesel. A few things about diesels. Clean fuel is a must! The properties of diesel fuel are much different than gas. As such, it is important to fill your truck at high volume fuel stations. Stay away from the mom and pop stores that sell diesel. Try and fill up between 1/4 and 1/2 tank to keep cleaner fuel in the tank, as it does recirculate. After a long trip, keep the tank topped off to minimize condensation in the tank. Keep that fuel filter changed at 15K miles or less. I cannot stress this enough. If possible have an additional fuel filter installed. Your dealer may be able to help you with this.
I am enjoying 21 MPG solo on freeway trips and 13 mpg towing in areas like the hills of WVA and VA. On the flats in the Southern states I get around 15 mpg towing.
