2017 GMC SIERRA automatic transmission

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-9955992) - 2017 - crc - 4/18/17
Driving and Operating 287
6-Speed Automatic TransmissionGear before shifting from
D (Drive) to L (Manual Mode) 6th 5th 4th 3rd 2nd 1st
Range after shifting from
D (Drive) to L (Manual Mode) L4 L4 L3 L2 L2 L1
8-Speed Automatic Transmission Gear before
shifting from
D (Drive) to
L (Manual Mode) 8th 7th 6th 5th 4th 3rd 2nd 1st
Range after
shifting from
D (Drive) to
L (Manual Mode) –
Tow/Haul not
engaged L6 L6 L5 L4 L3 L3 L2 L1
Range after
shifting from
D (Drive) to
L (Manual Mode) –
Tow/Haul engaged L6 L5 L4 L3 L3 L3 L2 L1 Grade Braking is not available when
Range Selection Mode is active.
See
Tow/Haul Mode 0288.
While using Range Selection Mode,
cruise control and the Tow/Haul
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.
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 the vehicle
is stuck, do not spin the tires.
When stopping on a hill, use the
brakes to hold the vehicle in
place.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-9955992) - 2017 - crc - 4/18/17
288 Driving and Operating
Low Traction Mode
If equipped, Low Traction Mode
assists in vehicle acceleration when
road conditions are slippery, such
as with ice or snow. While the
vehicle is at a stop, select L2 using
Range Selection Mode. This will
limit torque to the wheels and help
to prevent the tires from spinning.
Tow/Haul Mode
Vehicles with an automatic
transmission have a Tow/Haul
Mode. The Tow/Haul Mode adjusts
the transmission shift pattern to
reduce shift cycling. This providesincreased performance, vehicle
control, and enhanced transmission
and engine cooling when driving
down steep hills or mountain
grades, when towing, or when
hauling heavy loads.
The selector button is on the end of
the shift lever. Turn the Tow/Haul
Mode on and off by pressing the
button. When the Tow/Haul Mode is
enabled, a light on the instrument
cluster will come on.
For an eAssist vehicle, the Stop/
Start function will become
unavailable when Tow/Haul Mode is
active.
For an eAssist vehicle, the
Regenerative Braking functionality is
disabled when using the Tow/Haul
Mode. See the eAssist supplement.
See
Tow/Haul Mode Light 0147 and
Hill and Mountain Roads 0262.
Also see “Tow/Haul Mode” under
Towing Equipment 0340.Tow/Haul Mode Grade Braking
Tow/Haul Mode Grade Braking is
only enabled while the Tow/Haul
Mode is selected and the vehicle is not in the Range Selection Mode.
See
“Tow/Haul Mode” listed
previously and Manual Mode0286.
Tow/Haul Mode Grade Braking
assists in maintaining desired
vehicle speeds when driving on
downhill grades by using the engine
and transmission to slow the
vehicle.
If equipped, on vehicles with a
gasoline engine, to disable or
enable Tow/Haul Grade Braking
within the current ignition key cycle,
press and hold the Tow/Haul button
for five seconds. When the button is
released, the requested mode
change is made. A DIC message is
displayed. See Transmission
Messages 0164.
On vehicles with a diesel engine,
Tow/Haul Mode Grade Braking can
be enabled or disabled by pressing
the Tow/Haul Mode button. Use the
exhaust brake and Tow/Haul Mode
for maximum grade braking.
See Towing Equipment 0340.
For other forms of grade braking,
see Automatic Transmission 0283
and Cruise Control 0302.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-9955992) - 2017 - crc - 4/18/17
302 Driving and Operating
When enabled, if the vehicle is at a
speed above 22 km/h (14 mph) and
less than 60 km/h (37 mph), a DIC
message will display. SeeVehicle
Speed Messages 0167.
Locking Rear Axle
Vehicles with a locking rear axle can
give more traction on snow, mud,
ice, sand, or gravel. It works like a
standard axle most of the time, but
when traction is low, this feature will
allow the rear wheel with the most
traction to move the vehicle.
Cruise Control
With cruise control a speed of about
40 km/h (25 mph) or more can be
maintained without keeping your
foot on the accelerator. Cruise
control does not work at speeds
below about 40 km/h (25 mph).
{Warning
Cruise control can be dangerous
where you cannot drive safely at
a steady speed. Do not use
cruise control on winding roads or
in heavy traffic.
Cruise control can be dangerous
on slippery roads. On such roads,
fast changes in tire traction can
cause excessive wheel slip, and
you could lose control. Do not use
cruise control on slippery roads. If equipped with an Allison or
Hydra-Matic 6-speed automatic
transmission, see
“Tow/Haul Mode
Grade Braking” underTow/Haul
Mode 0288 for an explanation of
how cruise control interacts with the
Range Selection Mode, Tow/Haul
Mode, and Grade Braking systems.
If the cruise control is being used
and the Traction Control System
(TCS) or StabiliTrak begins to limit
wheel spin, the cruise control will
automatically disengage. See
Traction Control/Electronic Stability
Control 0299. If a collision alert
occurs when cruise control is
activated, cruise control is
disengaged. See Forward Collision
Alert (FCA) System 0308. When
road conditions allow you to safely
use it again, cruise control can be
turned back on.
If the brakes are applied, the cruise
control disengages.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-9955992) - 2017 - crc - 4/18/17
304 Driving and Operating
Reducing Speed While Using
Cruise Control
If the cruise control system is
already activated:
.Press and hold SET– until the
desired lower speed is reached,
then release it.
. To slow down in small
increments, briefly press SET– .
For each press, the vehicle goes
about 1.6 km/h (1 mph) slower.
The speedometer reading can be
displayed in either English or metric
units. See Instrument Cluster 0132.
The increment value used depends
on the units displayed.
Passing Another Vehicle While
Using Cruise Control
Use the accelerator pedal to
increase the vehicle speed. When
you take your foot off the pedal, the
vehicle will slow down to the
previous set cruise speed. While
pressing the accelerator pedal or
shortly following the release to
override cruise control, briefly pressing SET–
will result in cruise
control set to the current vehicle
speed.
Using Cruise Control on Hills
How well the cruise control works
on hills depends on the vehicle
speed, the load, and the steepness
of the hills. When going up steep
hills, pressing the accelerator pedal
may be necessary to maintain
vehicle speed.
While going downhill:
. Vehicles with a 6-speed
automatic transmission and a
gasoline engine have Cruise
Grade Braking to help maintain
driver selected speed.
Cruise Grade Braking is enabled
when the vehicle is started and
cruise control is active. It is not
enabled in Range Selection
Mode. It assists in maintaining
driver selected speed when
driving on downhill grades by
using the engine and
transmission to slow the vehicle. To disable and enable Cruise
Grade Braking for the current
ignition key cycle, press and
hold the Tow/Haul button for
five seconds. A DIC message
displays. See
Transmission
Messages 0164.
. Vehicles with a diesel engine
have Cruise Grade Braking
enabled when Tow/Haul Mode is
on, the exhaust brake is on,
or both are on.
For other forms of descent control,
see Hill Descent Control (HDC)
0 301, Automatic Transmission
0 283, and Tow/Haul Mode 0288.
Ending Cruise Control
There are four ways to end cruise
control:
. Step lightly on the brake pedal.
. Press
*.
. Shift the transmission to
N (Neutral).
. To turn off cruise control,
press
5.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-9955992) - 2017 - crc - 4/18/17
322 Driving and Operating
When towing at high altitude on
steep uphill grades, consider the
following: Engine coolant will boil at
a lower temperature than at normal
altitudes. If the engine is turned off
immediately after towing at high
altitude on steep uphill grades, the
vehicle may show signs similar to
engine overheating. To avoid this,
let the engine run while parked,
preferably on level ground, with the
transmission in P (Park) for a few
minutes before turning the engine
off. If the overheat warning comes
on, seeEngine Overheating 0376.
Parking on Hills
{Warning
Parking the vehicle on a hill with
the trailer attached can be
dangerous. If something goes
wrong, the rig could start to move.
People can be injured, and both
the vehicle and the trailer can be
damaged. When possible, always
park the rig on a flat surface. If parking the rig on a hill:
1. Press the brake pedal, but do not shift into P (Park) yet. Turn
the wheels into the curb if
facing downhill or into traffic if
facing uphill.
2. Have someone place chocks under the trailer wheels.
3. When the wheel chocks are in place, release the regular
brakes until the chocks absorb
the load.
4. Reapply the brake pedal. Then apply the parking brake and
shift into P (Park).
5. Release the brake pedal.Leaving After Parking on a Hill
1. Apply and hold the brake pedal.
2. Start the engine.
3. Shift into a gear.
4. Release the parking brake. 5. Let up on the brake pedal.
6. Drive slowly until the trailer is
clear of the chocks.
7. Stop and have someone pick up and store the chocks.
Maintenance when Trailer
Towing
The vehicle needs service more
often when pulling a trailer. See
Maintenance Schedule 0455.
Things that are especially important
in trailer operation are automatic
transmission fluid, engine oil, axle
lubricant, belts, cooling system, and
brake system. It is a good idea to
inspect these before and during
the trip.
Check periodically to see that all
hitch nuts and bolts are tight.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-9955992) - 2017 - crc - 4/18/17
Driving and Operating 325
1500/2500/3500 Series Pickups–SAE J2807 Compliant
Vehicle Axle Ratio Maximum Trailer
Weight (c) GCWR (a)
1500 Series 2WD Regular Cab Standard Box 4.3L V6 3.23 2 722 kg (6,000 lb) 4 990 kg (11,000 lb)
4.3L V6 4.10 2 087 kg (4,600 lb) 4 309 kg (9,500 lb)
5.3L V8 3.08 3 130 kg (6,900 lb) 5 443 kg (12,000 lb)
5.3L V8 3.42 4 037 kg (8,900 lb) 6 350 kg (14,000 lb)
1500 Series 2WD Double Cab Standard Box 4.3L V6 3.23 2 540 kg (5,600 lb) 4 990 kg (11,000 lb)
5.3L V8 3.08 2 903 kg (6,400 lb) 5 443 kg (12,000 lb)
5.3L V8, 6-speed automatic
transmission 3.42 4 264 kg (9,400 lb) 6 804 kg (15,000 lb)
5.3L V8, 8-speed automatic
transmission –Conventional
Trailer 3.42 4 264 kg (9,400 lb) 6 804 kg (15,000 lb)
5.3L V8, 8-speed automatic
transmission –Gooseneck/
Fifth-Wheel Trailer 3.42 4 128 kg (9,100 lb) 6 804 kg (15,000 lb)

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-9955992) - 2017 - crc - 4/18/17
326 Driving and Operating
1500/2500/3500 Series Pickups–SAE J2807 Compliant
Vehicle Axle Ratio Maximum Trailer
Weight (c) GCWR (a)
5.3L V8, 8-speed automatic
transmission with Enhanced
Towing Package –Conventional
Trailer 3.42 5 035 kg (11,100 lb) 7 575 kg (16,700 lb)
5.3L V8, 8-speed automatic
transmission with Enhanced
Towing Package –Gooseneck/
Fifth-Wheel Trailer 3.42 4 990 kg (11,000 lb) 7 575 kg (16,700 lb)
5.3L V8 –Conventional Trailer 3.735 035 kg (11,100 lb) 7 575 kg (16,700 lb)
5.3L V8 –Gooseneck/Fifth-Wheel
Trailer 3.73
4 990 kg (11,000 lb) 7 575 kg (16,700 lb)
6.2L V8 –Conventional Trailer 3.234 264 kg (9,400 lb) 6 804 kg (15,000 lb)
6.2L V8 –Gooseneck/Fifth-Wheel
Trailer 3.23
4 082 kg (9,000 lb) 6 804 kg (15,000 lb)
6.2L V8 –Conventional Trailer 3.425 670 kg (12,500 lb) 8 255 kg (18,200 lb)
6.2L V8 –Gooseneck/Fifth-Wheel
Trailer 3.42
5 307 kg (11,700 lb) 8 255 kg (18,200 lb)
1500 Series 2WD Crew Cab Standard Box 4.3L V6 3.232 449 kg (5,400 lb) 4 990 kg (11,000 lb)

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-9955992) - 2017 - crc - 4/18/17
Driving and Operating 327
1500/2500/3500 Series Pickups–SAE J2807 Compliant
Vehicle Axle Ratio Maximum Trailer
Weight (c) GCWR (a)
5.3L V8 3.08 2 858 kg (6,300 lb) 5 443 kg (12,000 lb)
5.3L V8 –Conventional Trailer 3.424 218 kg (9,300 lb) 6 804 kg (15,000 lb)
5.3L V8, 6-speed automatic
transmission –Gooseneck/
Fifth-Wheel Trailer 3.42
3 901 kg (8,600 lb) 6 804 kg (15,000 lb)
5.3L V8, 8-speed automatic
transmission –Gooseneck/
Fifth-Wheel Trailer 3.42
3 674 kg (8,100 lb) 6 804 kg (15,000 lb)
5.3L V8, 8-speed automatic
transmission with Enhanced
Towing Package –Conventional
Trailer 3.42
4 944 kg (10,900 lb) 7 575 kg (16,700 lb)
5.3L V8, 8-speed automatic
transmission with Enhanced
Towing Package –Gooseneck/
Fifth-Wheel Trailer 3.42
4 808 kg (10,600 lb) 7 575 kg (16,700 lb)
5.3L V8 –Conventional Trailer 3.734 990 kg (11,000 lb) 7 575 kg (16,700 lb)
5.3L V8 –Gooseneck/Fifth-Wheel
Trailer 3.73
4 853 kg (10,700 lb) 7 575 kg (16,700 lb)
6.2L V8 –Conventional Trailer 3.234 218 kg (9,300 lb) 6 804 kg (15,000 lb)