tow GMC SIERRA 2018 Repair Manual

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 0268. 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) 0294.
. Turn off Lane Keep Assist (LKA)
when towing.
{Warning
When 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 0264.
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
Driving and Operating 305
tires, and mirrors. Get familiar with
the handling and braking of the rig.
If the trailer has electric brakes, start
the combination moving and then
apply the trailer brake controller by
hand to be sure the brakes work.
During the trip, check occasionally
to be sure that the load is secure
and the lamps and any trailer
brakes still work.
Following Distance
Stay at least twice as far behind the
vehicle ahead as you would when
driving the vehicle without a trailer.
This can help to avoid heavy
braking and sudden turns.
Passing
More passing distance is needed
when towing a trailer. The
combination will not accelerate as
quickly and is longer so it is
necessary to go much farther
beyond the passed vehicle before
returning to the lane.
Backing Up
Hold the bottom of the steering
wheel with one hand. To move the
trailer to the left, move that hand to
the left. To move the trailer to the
right, move your hand to the right.
Always back up slowly and,
if possible, have someone
guide you.
Making TurnsCaution
Making very sharp turns while
trailering could cause the trailer to
come in contact with the vehicle.
The vehicle could be damaged.
Avoid making very sharp turns
while trailering.
When turning with a trailer, make
wider turns than normal. Do this so
the trailer will not strike soft
shoulders, curbs, road signs, trees,
or other objects. Avoid jerky or
sudden maneuvers. Signal well in
advance. If the trailer turn signal bulbs burn
out, the arrows on the instrument
cluster will still flash for turns. It is
important to check occasionally to
be sure the trailer bulbs are still
working.
Turn Signals When Towing a
Trailer
The turn signal indicators on the
instrument cluster flash whenever
signaling a turn or lane change.
Properly hooked up, the trailer
lamps also flash, telling other
drivers the vehicle is turning,
changing lanes, or stopping.
When towing a trailer, the arrows on
the instrument cluster flash for turns
even if the bulbs on the trailer are
burned out.
Check occasionally to be sure the
trailer bulbs are still working.

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
gearbefore 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 0271.
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 0363.
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.
.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 307
Maintenance when Trailer
Towing
The vehicle needs service more
often when pulling a trailer. See
Maintenance Schedule0448.
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 0255.
{Warning
The 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.
Caution
Pulling 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 0248 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
308 Driving and Operating
The following information has many
time-tested, important trailering tips
and safety rules. Many of these are
important for your safety and that of
your passengers. Read this section
carefully before pulling a trailer.
Weight of the Trailer
Safe trailering requires monitoring
the weight, speed, altitude, road
grades, outside temperature, and
how frequently the vehicle is used to
pull a trailer. Take into consideration
any special equipment on the
vehicle, and the amount of tongue
weight the vehicle can carry. See
“Weight of the Trailer Tongue”later
in this section for more information. Trailer weight rating (TWR) for
pickup models is calculated
assuming the tow vehicle has the
driver, a front seat passenger, and
all required trailering equipment.
Weight of additional optional
equipment, passengers, and cargo
in the tow vehicle must be
subtracted from the trailer weight
rating.
Ask your dealer for trailering
information or advice.
A step-bumper trailer hitch is limited
to 2,271 kg (5,000 lb) total trailer
weight. If a trailer hitch ball is added
to the step-bumper, ensure that the
ball is rated to pull the trailer's
weight.For kingpin weight and trailer
tongue weight information, see
“Weight of the Trailer Tongue”
later
in this section.
Use the following chart to determine
how much the vehicle can weigh,
based upon the vehicle model and
options.
Weights listed apply for
conventional trailers and
gooseneck/fifth-wheel trailers unless
otherwise noted.

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 3.735 035 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
5 262 kg (11,600 lb) 8 255 kg (18,200 lb)
1500 Series 2WD Crew Cab Standard Box 5.3L V8 3.082 858 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 311
1500/2500/3500 Series Pickups–SAE J2807 Compliant
Vehicle Axle Ratio Maximum Trailer
Weight (c) GCWR (a)
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
3 856 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 3.734 990 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)

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 3.425 398 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 3.232 495 kg (5,500 lb) 4 990 kg (11,000 lb)
5.3L V8 3.082 903 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 3.734 990 kg (11,000 lb) 7 575 kg (16,700 lb)
6.2L V8 3.234 218 kg (9,300 lb) 6 804 kg (15,000 lb)
6.2L V8 3.425 670 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 3.424 173 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 3.734 899 kg (10,800 lb) 7 575 kg (16,700 lb)
6.2L V8 –Conventional Trailer 3.234 128 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 3.425 352 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 3.082 767 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 315
1500/2500/3500 Series Pickups–SAE J2807 Compliant
Vehicle Axle Ratio Maximum Trailer
Weight (c) GCWR (a)
5.3L V8 –Conventional Trailer 3.424 128 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 3.734 853 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 3.234 082 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 3.425 307 kg (11,700 lb) 8 029 kg (17,700 lb)