2006 GMC Sierra/A1000 Shift Points

[RAVC1]

My father-in-law purchased this vehicle last summer and has urged the dealer and Allison to change the shift points in the 6-speed A1000 to lower the thresholds for entering 5th & 6th gears. Allison has told him they will do this for him after his warranty expires.

Do any of the chip manufacturers address this issue successfully?

Please advise.

Thanks,

Rick

[More Power]

The 5-speed Allison upshifts into 5th at just over 50-mph, which is just under 1500-rpm. I really wouldn't want it shift go into OD any sooner. Lugging a diesel in OD lockup is hard on the torque converter. From a purely fuel economy position, your best fuel economy will come at 1800.

Jim