GMC Yukon Denalid Owner's Manual page 149

Your vehicle's transmission uses adaptive shift
controls. Adaptive shift controls continually
compares key shift parameters to pre programmed
ideal shift conditions stored in the transmissions
computer. The transmission constantly makes
adjustments to improve vehicle performance
according to the way the vehicle is being used,
such as with a heavy load. During this adaptive
shift controls process, some shifts may feel
different as the transmission determines the best
settings for a particular shift.
Driver Shift Control (DSC)
Your vehicle has a Driver Shift Control (DSC).
The DSC controls the vehicle's transmission.
To use this feature, do the following:
1. Move the shift lever to the MANUAL
MODE (M).
2. Press the plus/minus button, to upshift or
downshift selecting the desired range of
gears for your current driving conditions.
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