transmission GMC SIERRA DENALI 2018 Service Manual

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
288 Driving and Operating 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.
.
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)
0 284 , Automatic Transmission
0 265 , and Tow/Haul Mode 0 271 . 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 .
Erasing Speed Memory
The cruise control set speed is
erased from memory if
5 is pressed
or the ignition is turned off. Driver Assistance
Systems This vehicle may have features that
work together to help avoid crashes
or reduce crash damage while
driving, backing, and parking. Read
this entire section before using
these systems.
{ WarningDo not rely on the Driver
Assistance Systems. These
systems do not replace the need
for paying attention and driving
safely. You may not hear or feel
alerts or warnings provided by
these systems. Failure to use
proper care when driving may
result in injury, death, or vehicle
damage. See Defensive Driving
0 236 .
(Continued)

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
304 Driving and Operating .
The trailer must be equipped
with brakes adequate for the
intended use. A loaded trailer
weighing more than 900 kg
(2,000 lb) must be equipped with
its own brake system, with
brakes working on all axles.
Trailer braking equipment
conforming to Canadian
Standards Association (CSA)
requirement CAN3-D313, or its
equivalent, is recommended.
.
Do not tow a trailer during the
first 800 km (500 mi) to prevent
damage to the engine, axle,
or other parts.
.
Then during the first 800 km
(500 mi) of trailer towing, do not
drive over 80 km/h (50 mph) and
do not make starts at full throttle.
.
The vehicle can tow in D (Drive)
but Manual Mode is
recommended. See Manual
Mode 0 268 . Use a lower gear if
the transmission shifts too often. .
Vehicles can tow in D (Drive).
The Tow/Haul Mode may be
used if the transmission shifts
too often. See Tow/Haul Mode
0 271 .
.
The Forward Automatic Braking
System should be set to Off
when towing. See Forward
Automatic Braking (FAB) 0 294 .
.
Turn off Lane Keep Assist (LKA)
when towing.
{ WarningWhen towing a trailer, exhaust
gases may collect at the rear of
the vehicle and enter if the
liftgate, trunk/hatch, or rear-most
window is open.
When towing a trailer:
.
Do not drive with the
liftgate, trunk/hatch,
or rear-most window open.
.
Fully open the air outlets on
or under the instrument
panel.
(Continued) Warning (Continued) .
Also adjust the climate
control system to a setting
that brings in only outside
air. See “ Climate Control
Systems ” in the Index.
For more information about
carbon monoxide, see Engine
Exhaust 0 264 .
Towing a trailer requires a certain
amount of experience. The
combination you are driving is
longer and not as responsive as the
vehicle itself. Get acquainted with
the handling and braking of the rig
before setting out for the open road.
The structure, tires, and brakes of
the trailer must be rated to carry the
load. Inadequate trailer equipment
can cause the combination to
operate in an unexpected or unsafe
manner.
Before starting, check all trailer hitch
parts and attachments, safety
chains, electrical connectors, lamps,

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
306 Driving and Operating Driving on Grades Reduce speed and shift to a lower
gear before starting down a long or
steep downgrade. If the
transmission is not shifted down, the
brakes might get hot and no longer
work well.
Vehicles can tow in D (Drive). Shift
the transmission to a lower gear if
the transmission shifts too often
under heavy loads and/or hilly
conditions.
The Tow/Haul Mode may be used if
the transmission shifts too often.
See Tow/Haul Mode 0 271 .
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, see Engine Overheating 0 363 .
Parking on Hills
{ WarningParking 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.
.
Start the engine.
.
Shift into a gear.
.
Release the parking brake.
2. Let up on the brake pedal.
3. Drive slowly until the trailer is
clear of the chocks.
4. Stop and have someone pick
up and store the chocks.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Driving and Operating 307Maintenance when Trailer
Towing The vehicle needs service more
often when pulling a trailer. See
Maintenance Schedule 0 448 .
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.
Engine Cooling When Trailer
Towing The cooling system may temporarily
overheat during severe operating
conditions. See Engine Overheating
0 363 . Trailer Towing If the vehicle has a diesel engine,
see the Duramax diesel
supplement.
Do not tow a trailer during break-in.
See New Vehicle Break-In 0 255 .
{ WarningThe driver can lose control when
pulling a trailer if the correct
equipment is not used or the
vehicle is not driven properly. For
example, if the trailer is too heavy
or the trailer brakes are
inadequate for the load, the
vehicle may not stop as expected.
The driver and passengers could
be seriously injured. The vehicle
may also be damaged; the
resulting repairs would not be
covered by the vehicle warranty.
Pull a trailer only if all the steps in
this section have been followed.
Ask your dealer for advice and
information about towing a trailer
with the vehicle. CautionPulling a trailer improperly can
damage the vehicle and result in
costly repairs not covered by the
vehicle warranty. To pull a trailer
correctly, follow the advice in this
section and see your dealer for
important information about
towing a trailer with the vehicle.
See Vehicle Load Limits 0 248 for
more information about the vehicle's
maximum load capacity.
To identify the trailering capacity of
the vehicle, read the information in
“ Weight of the Trailer ” later in this
section.
Trailering is different than just
driving the vehicle by itself.
Trailering means changes in
handling, acceleration, braking,
durability, and fuel economy.
Successful, safe trailering takes
correct equipment, and it has to be
used properly.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Driving and Operating 3091500/2500/3500 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-11349177) - 2018 - CRC - 10/17/17
310 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 3.73 5 035 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 3.23 4 264 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 3.42 5 670 kg (12,500 lb) 8 255 kg (18,200 lb)
6.2L V8 – Gooseneck/Fifth-Wheel
Trailer 3.42 5 262 kg (11,600 lb) 8 255 kg (18,200 lb)
1500 Series 2WD Crew Cab Standard Box
5.3L V8 3.08 2 858 kg (6,300 lb) 5 443 kg (12,000 lb)

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Driving and Operating 3111500/2500/3500 Series Pickups – SAE J2807 Compliant
Vehicle Axle Ratio Maximum Trailer
Weight (c) GCWR (a)
5.3L V8 – Conventional Trailer 3.42 4 218 kg (9,300 lb) 6 804 kg (15,000 lb)
5.3L V8, 6-speed automatic
transmission – Gooseneck/
Fifth-Wheel Trailer 3.42 3 856 kg (8,500 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 3.73 4 990 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 3.23 4 218 kg (9,300 lb) 6 804 kg (15,000 lb)

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
312 Driving and Operating 1500/2500/3500 Series Pickups – SAE J2807 Compliant
Vehicle Axle Ratio Maximum Trailer
Weight (c) GCWR (a)
6.2L V8 – Gooseneck/Fifth-Wheel
Trailer 3.23 3 765 kg (8,300 lb) 6 804 kg (15,000 lb)
6.2L V8 – Conventional Trailer 3.42 5 398 kg (11,900 lb) 8 029 kg (17,700 lb)
6.2L V8 – Gooseneck/Fifth-Wheel
Trailer 3.42 4 763 kg (10,500 lb) 8 029 kg (17,700 lb)
1500 Series 2WD Crew Cab Short Box (b)
4.3L V6 3.23 2 495 kg (5,500 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 3.42 4 218 kg (9,300 lb) 6 804 kg (15,000 lb)
5.3L V8, 8-speed automatic
transmission with Enhanced
Towing Package 3.42 4 990 kg (11,000 lb) 7 575 kg (16,700 lb)
5.3L V8 3.73 4 990 kg (11,000 lb) 7 575 kg (16,700 lb)
6.2L V8 3.23 4 218 kg (9,300 lb) 6 804 kg (15,000 lb)
6.2L V8 3.42 5 670 kg (12,500 lb) 8 255 kg (18,200 lb)

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
314 Driving and Operating 1500/2500/3500 Series Pickups – SAE J2807 Compliant
Vehicle Axle Ratio Maximum Trailer
Weight (c) GCWR (a)
5.3L V8 3.08 2 812 kg (6,200 lb) 5 443 kg (12,000 lb)
5.3L V8 – Gooseneck/Fifth Wheel 3.08 2 767 kg (6,100 lb) 5 443 kg (12,000 lb)
5.3L V8 – Conventional Trailer 3.42 4 173 kg (9,200 lb) 6 804 kg (15,000 lb)
5.3L V8 – Gooseneck/Fifth Wheel 3.42 4 082 kg (9,000 lb) 6 804 kg (15,000 lb)
5.3L V8, 8-speed automatic
transmission with Enhanced
Towing Package 3.42 4 899 kg (10,800 lb) 7 575 kg (16,700 lb)
5.3L V8 3.73 4 899 kg (10,800 lb) 7 575 kg (16,700 lb)
6.2L V8 – Conventional Trailer 3.23 4 128 kg (9,100 lb) 6 804 kg (15,000 lb)
6.2L V8 – Gooseneck/Fifth-Wheel
Trailer 3.23 3 901 kg (8,600 lb) 6 804 kg (15,000 lb)
6.2L V8 – Conventional Trailer 3.42 5 352 kg (11,800 lb) 8 029 kg (17,700 lb)
6.2L V8 – Gooseneck/Fifth-Wheel
Trailer 3.42 4 990 kg (11,000 lb) 8 029 kg (17,700 lb)
1500 Series 4WD Crew Cab Standard Box
5.3L V8 – Conventional Trailer 3.08 2 767 kg (6,100 lb) 5 443 kg (12,000 lb)
5.3L V8 – Gooseneck/Fifth-Wheel
Trailer 3.08 2 722 kg (6,000 lb) 5 443 kg (12,000 lb)

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Driving and Operating 3151500/2500/3500 Series Pickups – SAE J2807 Compliant
Vehicle Axle Ratio Maximum Trailer
Weight (c) GCWR (a)
5.3L V8 – Conventional Trailer 3.42 4 128 kg (9,100 lb) 6 804 kg (15,000 lb)
5.3L V8 – 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 4 853 kg (10,700 lb) 7 575 kg (16,700 lb)
5.3L V8, 8-speed automatic
transmission with Enhanced
Towing Package – Gooseneck/
Fifth Wheel Trailer 3.42 4 627 kg (10,200 lb) 7 575 kg (16,700 lb)
5.3L V8 – Conventional Trailer 3.73 4 853 kg (10,700 lb) 7 575 kg (16,700 lb)
5.3L V8 – Gooseneck/Fifth-Wheel
Trailer 3.73 4 627 kg (10,200 lb) 7 575 kg (16,700 lb)
6.2L V8 – Conventional Trailer 3.23 4 082 kg (9,000 lb) 6 804 kg (15,000 lb)
6.2L V8 – Gooseneck/Fifth-Wheel
Trailer 3.23 3 629 kg (8,000 lb) 6 804 kg (15,000 lb)
6.2L V8 – Conventional Trailer 3.42 5 307 kg (11,700 lb) 8 029 kg (17,700 lb)