GMC 2015 Sierra Denali Owner's Manual page 22

Transmission
Range Selection Mode
The Range Selection Mode button
is on the shift lever.
To enable Range Selection:
1. Move the shift lever to
M (Manual Mode). The current
range will appear next to the M.
This is the highest possible
range with all lower gears
accessible. As an example,
when 5 (Fifth) gear is selected,
1 (First) through 5 (Fifth) gears
are available.
2. Press the plus/minus buttons to
select the range of gears for
current driving conditions. See
Manual Mode on page 9-36.
While using Range Selection Mode,
cruise control and the Tow/Haul
mode can be used.
Grade Braking is not available when
Range Selection Mode is active.
See Tow/Haul Mode on page 9-39.
Four-Wheel Drive
If the vehicle has Four-Wheel Drive,
the engine's driving power can be
sent to all four wheels for extra
traction.
Transfer Case Controls
The vehicle will have one of two
styles of transfer case controls. Use
these controls to shift into and out of
the different four-wheel drive
modes.
In Brief
Electronic Transfer Case
This transfer case knob is to the left
of the steering column.
1-15