You cant gross 19 - 26K consistently day in & out or at least once a week with a 5-speed no matter what you put in it....mine broke twice not pulling a trailer! I used to Hot Shot for a living with the other truck with the 5-speed and anyone who pulls a trailer professionally will tell you that 5 speeds are junk. The transmission is under rated for the truck & the Cummins and by the time you spend all of the money and time on trying to upgrade a 5-speed, you could have had a new 6 speed transmission & new front driveshaft for about $2500.00 and not sink money into a black hole of a transmission.