2008 GMC SIERRA Owner's Manual

6. Release the parking brake only after the vehicle
being towed is rmly attached to the tow vehicle.
7. Turn the ignition to LOCK/OFF.
Towing a Trailer
If your vehicle has a diesel engine, see the DURAMAX®
Diesel manual for more information.
Do not tow a trailer during break-in. SeeNew Vehicle
Break-In on page 2-22for more information.
{CAUTION:
If you do not use the correct equipment and
drive properly, you can lose control when you
pull a trailer. For example, if the trailer is too
heavy, the brakes may not work well — or even
at all. You and your passengers could be
seriously injured. Pull a trailer only if you have
followed all the steps in this section. Ask your
dealer for advice and information about towing
a trailer with your vehicle.Notice:Pulling a trailer improperly can damage
your vehicle and result in costly repairs not covered
by your warranty. To pull a trailer correctly, follow
the advice in this part, and see your dealer for
important information about towing a trailer with
your vehicle.
To identify the trailering capacity of your vehicle, you
should read the information in “Weight of the Trailer” that
appears later in this section.
Trailering is different than just driving your vehicle by
itself. Trailering means changes in acceleration, braking,
handling, durability and fuel economy. Successful,
safe trailering takes correct equipment, and it has to be
used properly.
That’s the reason for this part. In it are many time-tested,
important trailering tips and safety rules. Many of
these are important for your safety and that of your
passengers. So please read this section carefully before
you pull a trailer.
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If You Do Decide To Pull A Trailer
If you do, here are some important points:
There are many different laws, including speed limit
restrictions, having to do with trailering. Make sure
your rig will be legal, not only where you live
but also where you’ll be driving. A good source for
this information can be state or provincial police.
Consider using a sway control. See “Hitches” later
in this section.
Don’t tow a trailer at all during the rst 500 miles
(800 km) your new vehicle is driven. Your engine,
axle or other parts could be damaged.
Then, during the rst 500 miles (800 km) that you
tow a trailer, don’t drive over 50 mph (80 km/h)
and don’t make starts at full throttle. This helps your
engine and other parts of your vehicle wear in at
the heavier loads.
You can tow in DRIVE (D). You may want to shift
the transmission to THIRD (3), or FOURTH (4)
with the Allison or Hydra-matic 6-speed
transmissions, or if necessary, a lower gear
selection if the transmission shifts too often, such
as under heavy loads and/or hilly conditions.
SeeTow/Haul Mode Light on page 3-53.Three important considerations have to do with weight:
The weight of the trailer
The weight of the trailer tongue
The weight on your vehicle’s tires
Tow/Haul Mode
Press this button at the end
of the shift lever to enable/
disable the tow/haul mode.
Tow/Haul is a feature that assists when pulling a heavy
trailer or a large or heavy load. SeeTow/Haul Mode
on page 2-34for more information.
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Tow/Haul is designed to be most effective when the
vehicle and trailer combined weight is at least 75 percent
of the vehicle’s Gross Combined Weight Rating (GCWR).
See “Weight of the Trailer” later in the section. Tow/Haul
is most useful under the following driving conditions:
When pulling a heavy trailer or a large or heavy load
through rolling terrain.
When pulling a heavy trailer or a large or heavy load
in stop and go traffic.
When pulling a heavy trailer or a large or heavy load
in busy parking lots where improved low speed
control of the vehicle is desired.
Operating the vehicle in Tow/Haul when lightly loaded
or with no trailer at all will not cause damage. However,
there is no benet to the selection of Tow/Haul when
the vehicle is unloaded. Such a selection when unloaded
may result in unpleasant engine and transmission
driving characteristics and reduced fuel economy.
Tow/Haul is recommended only when pulling a heavy
trailer or a large or heavy load.
Weight of the Trailer
How heavy can a trailer safely be?
It depends on how you plan to use your rig. For
example, speed, altitude, road grades, outside
temperature and how much your vehicle is used to pull
a trailer are all important. It can also depend on any
special equipment that you have on your vehicle,
and the amount of tongue weight the vehicle can carry.
See “Weight of the Trailer Tongue” later in this
section for more information.
Maximum trailer weight is calculated assuming only the
driver is in the tow vehicle and it has all the required
trailering equipment. The weight of additional optional
equipment, passengers and cargo in the tow vehicle
must be subtracted from the maximum trailer weight.
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Use one of the following charts to determine how much
your vehicle can weigh, based upon your vehicle
model and options.
C-1500 Regular Cab
Standard Box (2WD)*Axle Ratio Maximum Trailer Weight GCWR**
4.3L V63.23
3.734,800 lbs (2 177 kg)
5,300 lbs (2 404 kg)9,500 lbs (4 309 kg)
10,000 lbs (4 536 kg)
4.8L V83.23
3.735,200 lbs (2 359 kg)
7,200 lbs (3 266 kg)10,000 lbs (4 536 kg)
12,000 lbs (5 443 kg)
5.3L V83.42
3.737,200 lbs (3 266 kg)
8,200 lbs (3 719 kg)12,000 lbs (5 443 kg)
13,000 lbs (5 897 kg)
*Fifth-wheel or gooseneck kingpin weight 15 percent to 25 percent of trailer weight up to 1,500 lbs (680 kg) maximum.
**The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and
trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should not be
exceeded.
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C-1500 Extended Cab
Standard Box (2WD)*Axle Ratio Maximum Trailer Weight GCWR+
4.3L V63.23
3.734,300 lbs (1 950 kg)
4,800 lbs (2 177 kg)9,500 lbs (4 309 kg)
10,000 lbs (4 536 kg)
4.8L V83.23
3.734,700 lbs (2 132 kg)
6,700 lbs (3 039 kg)10,000 lbs (4 536 kg)
12,000 lbs (5 443 kg)
5.3L V83.42
3.736,700 lbs (3 039 kg)
7,700 lbs (3 493 kg)12,000 lbs (5 443 kg)
13,000 lbs (5 897 kg)
6.0L V8 3.73 8,800 lbs (3 992 kg) 14,000 lbs (6 350 kg)
6.0L V8** 3.73 10,200 lbs (4 627 kg) 15,500 lbs (7 031 kg)
*Fifth-wheel or gooseneck kingpin weight 15 percent to 25 percent of trailer weight up to 1,500 lbs (680 kg) maximum.
**NHT Enhanced Trailering Performance Package required.
+The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and
trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should not be
exceeded.
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C-1500 Extended Cab
Short Box (2WD)*Axle Ratio Maximum Trailer Weight GCWR**
4.3L V63.23
3.734,400 lbs (1 196 kg)
4,900 lbs (2 223 kg)9,500 lbs (4 309 kg)
10,000 lbs (4 536 kg)
4.8L V83.23
3.734,800 lbs (2 177 kg)
6,800 lbs (3 084 kg)10,000 lbs (4 536 kg)
12,000 lbs (5 448 kg)
5.3L V83.42
3.736,800 lbs (3 084 kg)
7,800 lbs (3 538 kg)12,000 lbs (5 448 kg)
13,000 lbs (5 902 kg)
6.0L V8 3.73 8,800 lbs (3 992 kg) 14,000 lbs (6 350 kg)
*This model is neither designed nor intended to tow fth-wheel or gooseneck trailers.
**The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and
trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should not be
exceeded.
C-1500 Crew Cab Short
Box (2WD)*Axle Ratio Maximum Trailer Weight GCWR+
4.8L V83.23
3.734,600 lbs (2 086 kg)
6,600 lbs (2 994 kg)10,000 lbs (4 536 kg)
12,000 lbs (5 443 kg)
5.3L V83.42
3.736,600 lbs (2 994 kg)
7,600 lbs (3 447 kg)12,000 lbs (5 443 kg)
13,000 lbs (5 897 kg)
6.0L V8 3.73 8,700 lbs (3 946 kg) 14,000 lbs (6 350 kg)
6.0L V8** 3.73 10,200 lbs (4 627 kg) 15,500 lbs (7 031 kg)
*This model is neither designed nor intended to tow fth-wheel or gooseneck trailers.
**NHT Enhanced Trailering Performance Package required.
+The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and
trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should not be
exceeded.
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C-1500 Regular Cab
Long Box (2WD)*Axle Ratio Maximum Trailer Weight GCWR**
4.3L V63.23
3.734,700 lbs (2 132 kg)
5,200 lbs (2 359 kg)9,500 lbs (4 309 kg)
10,000 lbs (4 536 kg)
4.8L V83.23
3.735,100 lbs (2 313 kg)
7,100 lbs (3 221 kg)10,000 lbs (4 536 kg)
12,000 lbs (5 448 kg)
5.3L V83.42
3.737,000 lbs (3 175 kg)
8,000 lbs (3 629 kg)12,000 lbs (5 443 kg)
13,000 lbs (5 896 kg)
*Fifth-wheel or gooseneck kingpin weight 15 percent to 25 percent of trailer weight up to 1,500 lbs (680 kg) maximum.
**The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and
trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should not be
exceeded.
C-1500 Extended Cab
Long Box (2WD)*Axle Ratio Maximum Trailer Weight GCWR**
5.3L V83.42
3.736,500 lbs (2 948 kg)
7,500 lbs (3 402 kg)12,000 lbs (5 443 kg)
13,000 lbs (5 897 kg)
*Fifth-wheel or gooseneck kingpin weight 15 percent to 25 percent of trailer weight up to 1,500 lbs (680 kg) maximum.
**The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and
trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should not be
exceeded.
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K-1500 Regular Cab
Standard Box (4WD)*Axle Ratio Maximum Trailer Weight GCWR**
4.3L V6 3.73 5,100 lbs (2 313 kg) 10,000 lbs (4 536 kg)
4.8L V83.42
4.105,900 lbs (2 676 kg)
7,900 lbs (3 583 kg)11,000 lbs (4 989 kg)
13,000 lbs (5 902 kg)
5.3L V83.73
4.107,900 lbs (3 583 kg)
8,900 lbs (4 037 kg)13,000 lbs (5 896 kg)
14,000 lbs (6 350 kg)
*Fifth-wheel or gooseneck kingpin weight 15 percent to 25 percent of trailer weight up to 1,500 lbs (680 kg) maximum.
*Fifth-wheel or gooseneck trailer rating limited to 7,300 lbs (3 311 kg).
**The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and
trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should not be
exceeded.
K-1500 Extended Cab
Standard Box (4WD)*Axle Ratio Maximum Trailer Weight GCWR+
4.8L V83.42
4.105,500 lbs (2 495 kg)
7,500 lbs (3 402 kg)11,000 lbs (4 989 kg)
13,000 lbs (5 897 kg)
5.3L V83.73
4.107,500 lbs (3 402 kg)
8,500 lbs (3 855 kg)13,000 lbs (5 897 kg)
14,000 lbs (6 350 kg)
6.0L V8 3.73 8,500 lbs (3 855 kg) 14,000 lbs (6 350 kg)
6.0L V8** 4.10 10,500 lbs (4 763 kg) 16,000 lbs (6 257 kg)
*Fifth-wheel or gooseneck kingpin weight 15 percent to 25 percent of trailer weight up to 1,500 lbs (680 kg) maximum.
**NHT Enhanced Trailering Performance Package required.
+The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and
trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should not be
exceeded.
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