Hrmm I was getting around 15-16 with my CC. It was a 6.5 td turbo 400 8 inch lift and 38's about the same with 35's and 4.10's My blazer has 4.10s on 33's and the turbo 400 so mileage could be better. Cant wait for the Nv4500
You're geared too low. Engine has to be screaming on the highway without OD and that configuration. Mine sounded like the end of the world in that configuration at 60mph. It's quieter with the 38's but still not happy past 65.what is GOOD diesel mileage, 88 1 ton 6.2 400t 4.56 gears 37" bfg's 10 mpg highway!!!!!!!!
Do you have to have a computer to do the 6.0l sawp?