Thanks Jeff, I just know even a mild tune on a 6.7 with twins and no defuel on the shifts will kill that trans pretty quick if its not setup correctly. Even in a medium duty application allison tells the cummins to cut back fuel on the shifts, once the shift is complete it gets its fuel back. It also limits a given amount of max torque per gear. Try taking a g56 under full boost and grabbing every gear without lifting off the throttle and see how long a 13" clutch lasts... Then look at an allison c2 and c3 clutch and compare size ... An allison shoots for a shift time of .50 seconds, during that time its in neutral, fastest time i can get without a tie up or a flare is low .3x and it works.... But its school bus shifting allison not gm shifting Allison. After i got all that figured out my p2 planet wasnt very happy 3 of them later i went billet and have been good for better then 100 passes handing that thing its ass every pass....