If you have the 48re automatic, I wouldn't do it with out first beefing it up. It is the weak link in the drive train for those years equipped with the 5.9. Smarty is probably the best tuner out there for the Cummins engines. The 5.9 is capable of tremendous power just in programming. If you go all out with injectors, turbo, after cooler, etc.., it is capable of well over 1,000 hp and 1,200 ft-lbs of torque.