I have a 2019 with the 6.4 and 3.73 gears. I have been doing a bit of hauling for folks, and I really like the truck. I hauled a 2004 extended cab short bed 2wd from Michigan to PA last weekend, then took it to South Carolina to pick up another car. With the truck on my 1800 pound trailer, it used some gas on the hills in PA. But it never slowed down. I averaged 11.6 for the trip and in the hills the worst tank I got was 9.54 mpg. I love the truck, and for what I do, I don't think a diesel would be cost effective.