GMC Sierra Denali 2017 Owner's Manual page 273

272 Driving and Operating
6-Speed Automatic Transmission
Gear before shifting from
D (Drive) to L (Manual Mode)
Range after shifting from
D (Drive) to L (Manual Mode)
8-Speed Automatic Transmission
Gear before
shifting from
8th
D (Drive) to
L (Manual Mode)
Range after
shifting from
D (Drive) to
L6
L (Manual Mode)
Tow/Haul not
engaged
Range after
shifting from
D (Drive) to L6
L (Manual Mode)
Tow/Haul engaged
6th 5th 4th
L4 L4 L3
7th 6th 5th 4th
L6 L5 L4 L3
L5 L4 L3 L3
Grade Braking is not available when
Range Selection Mode is active.
See Tow/Haul Mode 0 273.
3rd 2nd 1st
While using Range Selection Mode,
cruise control and the Tow/Haul
L2 L2 L1
Mode can be used.
If the vehicle has an exhaust brake,
it can also be used, but will not
automatically downshift the
transmission. See Exhaust Brake
in the Duramax diesel supplement.
3rd 2nd 1st
L3 L2 L1
L3 L2 L1
Low Traction Mode
If equipped, Low Traction Mode
assists in vehicle acceleration when
road conditions are slippery, such
Caution
Spinning the tires or holding the
vehicle in one place on a hill
using only the accelerator pedal
may damage the transmission.
The repair will not be covered by
the vehicle warranty. If you are
stuck, do not spin the tires. When
stopping on a hill, use the brakes
to hold the vehicle in place.