Just back from another 4,100 miles in the 06 251. No leaks. Average mileage on the Chevy chassis for the whole trip was 9.9 MPG. Many mountains climbed this trip with no problems at all West from OKC to the Grand Canyon, West to Morro Bay, North to the Golden Gate and back to Kansas on 80 thru Laramie, down to Denver then East to home. Most of the time I was able to pull the long grades at 60+ in 3rd. Temp gage only lifted of normal once on a long grade in 110 degree heat just East of Barstow. AC worked beautifully, both truck and ducted. The only problem in nearly 3 weeks was related to my puting my bulk on the end of the snap sofa and pulling the mounting screws free. OOPS. I plan to go by the Factory in July and will let them fix that. Each time I drive this unit, I am more impressed with how nicely it drives. 4X 400+ days on the run home and I could have driven farther each day, but I like to quit by 3PM and relax.