got a 2000 350 7.3L larait ...I am pulling around 3000 pounds includeing my trailer of just mowing stuff and it will pull it up hills but not like it should... it will creap around 40 miles a hour with my foot pedal to the floor...my freinds truck will pull the same load around 80 mph on the same hills ...something aint right...got to love these trucks ...any help thanks.