The Allison being a clutch on clutch transmission must literaly go into nuetral for a millisecond to complete the shift cleanly. If you alter that you will cause a tie up and start binding the clutches. If you do this you will be in 2 gears at once for a millisecond.
So figure a 7,000 lb truck running 500 hp with the pedal to the metal in 2 gears at once for a millisecond and the Alli loses. This is how the splines on the P2 planet and C2 hub strip.
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