I run a 2010 with mp8 and 13spd auto shift. Pull 48' skate board spread axle. Ive been out 5 1/2 months on this trip along. Mostly heavy steel loads. Always right at 80k gross. Run east to west coast. Least miles a week ive done this trip is 2,854/wk. I pull hills, desert, flat lands, snow, ice, you name it. I run the snot out of this mack! I get 6.7 - 8.1 mpg no problem. My family has always run macks. Telling ya am sold on this mp8. Shes pushing 500k miles dont use drop of oil. Or any fluids. Runs like a watch. Very pleased. This girl has big thighs and pulls good. It set at 450hp. On hills with heavy load 75+k gross. Drop to tenth and maintain 60mph up hill.keep rpms around 1525 - 1575. And the best part...when I do need maintance or parts every! Mack shop treats me right at the right price. Never had that any where else. Best luck to ya. Safe trips.