Oh and yes it gets worse mileage than my old 8 axle KW dump truck at 105,500 pounds with a 550 CAT and an 18 speed. I load the GMC to 26,000 GVW and 31,380 CGVW with the 12 ton equipment trailer and 17,000 pound 307 cat excavator behind it. Dragging 23,000 pounds of trailer and machine is a slow go drops MPG to about 4 and I am sure it is shorting the life of the transmission.
