Never have owned a diesel, but I can tell you that Ford did an excellent job with this engine, and with insulating the cab/engine compartment. Very smooth and quiet. Yes, it's going to rev and get louder on the hills, but not bad and I actually like to hear it work at those times. Mine has 3:73 gears as I found a great deal on dealer stock, but I'm only towing a out 7500 lbs. To get the 4:30's you will have to order your truck. If it isn't going to be a daily driver I would get the 4:30 gears no matter how much you tow as that is my only regret. Mileage claims have to be taken with a grain of salt. Needless to say it won't be great, but compared to the $8K additional sticker on the diesel, and the lower cost of gas, I still think I came out ahead. Awesome truck, I love it.