Yes it is a 6 speed not a allison

Is there any way you can make the changes ?

No there's nothing there just firmness and shiftpoints

i have checked i can increase the firmness but there is no setting for you to quicken shift.

Is there like advanced settings you need to use to be able to do that?

I didn't see anything that has the shift speed in the intune

I have just purchased a intune for my 2015 Silverado 2500hd 6.0 and the transmission is just not right it there a large delay in downshifting and when it up shifts at wot it's like torque management is on it does shift quick enough there like a small pause between shifts even know torque management ...