2010 GMC SAVANA trailer

Dividing the 900 lbs (408 kg) by 1.5 leaves only 600 lbs
(272 kg) of tongue weight that can be handled. Since
tongue weight is usually at least 10 percent of total
loaded trailer weight, expect that the largest trailer the
vehicle can properly handle is 6,000 lbs (2 721 kg).
It is important that the vehicle does not exceed any of
its ratings — GCWR, GVWR, RGAWR, Maximum Trailer
Rating or Tongue Weight. The only way to be sure it
is not exceeding any of these ratings is to weigh
the vehicle and trailer.
Total Weight on the Vehicle’s Tires
Be sure the vehicle’s tires are inflated to the upper limit
for cold tires. These numbers can be found on the
Certification label at the rear edge of the driver’s door or
seeLoading the Vehicle on page 5-17. Make sure not
to go over the GVW limit for the vehicle, or the GAWR,
including the weight of the trailer tongue. If using a
weight distributing hitch, make sure not to go over the
rear axle limit before applying the weight distribution
spring bars.
Hitches
It is important to have the correct hitch equipment.
Crosswinds, large trucks going by and rough roads are
a few reasons why the right hitch is needed.
Weight-Distributing Hitches and Weight
Carrying Hitches
A:Body to Ground Distance
B:Front of Vehicle
When using a weight-distributing hitch, the hitch must
be adjusted so the distance (A) remains the same both
before and after coupling the trailer to the tow vehicle.
If a step-bumper hitch will be used, the bumper could be
damaged in sharp turns. Make sure there is ample
room when turning to avoid contact between the trailer
and the bumper.
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If the loaded trailer being pulled will weigh more than
5,000 lbs (2 270 kg), be sure to use a properly mounted
weight-distributing hitch and sway control of the
proper size. This equipment is very important for proper
vehicle loading and good handling when driving.
Always use a sway control if the trailer will weigh more
than these limits. Ask a hitch dealer about sway
controls.
Will any holes need to be made in the body of the
vehicle when a trailer hitch is installed?
If using the wiring provided with the factory-installed
trailering package, no holes need to be made in
the body of the vehicle. However, if an aftermarket hitch
is installed, holes may need to be made in the body.
If holes are made in the body, then be sure to seal the
holes later when the hitch is removed. If the holes
are not sealed, deadly carbon monoxide (CO) from the
engine’s exhaust can get into the vehicle as well as
dirt and water. See “Carbon Monoxide” underEngine
Exhaust on page 3-38.
Safety Chains
Always attach chains between the vehicle and the
trailer. Cross the safety chains under the tongue of the
trailer to help prevent the tongue from contacting
the road if it becomes separated from the hitch. Always
leave just enough slack so the rig can turn. Never
allow safety chains to drag on the ground.
Tow/Haul Mode
Pressing this button at
the end of the shift lever
turns on and off the
tow/haul mode.
This indicator light on the
instrument panel cluster
comes on when the
tow/haul mode is on.
Tow/Haul is a feature that assists when pulling a heavy
trailer or a large or heavy load. SeeTow/Haul Mode
on page 3-33for more information.
5-33

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 benefit 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.
Trailer Brakes
A loaded trailer that weighs more than 1,500 lbs
(680 kg) needs to have its own brake system that is
adequate for the weight of the trailer. Be sure to read
and follow the instructions for the trailer brakes so
they are installed, adjusted and maintained properly.
Driving with a Trailer
{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.
Engine exhaust contains carbon monoxide (CO)
which cannot be seen or smelled. It can cause
unconsciousness and even death.
To maximize safety when towing a trailer:
•Have the exhaust system inspected for leaks
and make necessary repairs before starting
a trip.
•Never drive with the liftgate, trunk/hatch, or
rear-most window open.
•Fully open the air outlets on or under the
instrument panel.
•Adjust the Climate Control system to a setting
that brings in only outside air and set the fan
speed to the highest setting. See Climate
Control System in the Index.
For more information about carbon monoxide, see
Engine Exhaust on page 3-38
5-34

Towing a trailer requires a certain amount of experience.
Get to know the rig before setting out for the open
road. Get acquainted with the feel of handling and
braking with the added weight of the trailer. And always
keep in mind that the vehicle you are driving is now
longer and not as responsive as the vehicle is by itself.
Before starting, check all trailer hitch parts and
attachments, safety chains, electrical connectors, lamps,
tires and mirror adjustments. If the trailer has electric
brakes, start the vehicle and trailer moving and
then apply the trailer brake controller by hand to be sure
the brakes are working. This checks the electrical
connection at the same time.
During the trip, check occasionally to be sure that the
load is secure, and that the lamps and any trailer brakes
are still working.
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 situations that require heavy braking
and sudden turns.
Passing
More passing distance is needed when towing a trailer.
Because the rig is longer, 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.
Then, 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 Turns
Notice: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.
Turn Signals When Towing a Trailer
The arrows on the instrument panel 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
panel flash for turns even if the bulbs on the trailer are
burned out. For this reason you may think other
drivers are seeing the signal when they are not. It is
important to check occasionally to be sure the
trailer bulbs are still working.
5-35

Driving On Grades
Reduce speed and shift to a lower gearbeforestarting
down a long or steep downgrade. If the transmission is
not shifted down, the brakes might have to be used so
much that they would get hot and no longer work well.
The vehicle 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.
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 automatic transmission in P (Park) for a
few minutes before turning the engine off. If the overheat
warning comes on, seeEngine Overheating on
page 6-33.
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 the
transmission 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
brake pedal 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.
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Leaving After Parking on a Hill
1. Apply and hold the brake pedal while you:
•start the engine,
•shift into a gear, and
•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.
Maintenance When Trailer Towing
The vehicle needs service more often when pulling a
trailer. See this manual’s Maintenance Schedule
or Index for more information. 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.
Trailer Wiring Harness
The optional heavy-duty trailer wiring package includes
a wiring harness, with a seven-pin connector at the
rear of the vehicle and a four-wire harness assembly
under the driver side of the instrument panel. The
four-wire harness assembly comes without a connector.
If the vehicle does not have a trailer hitch, the
seven-wire harness assembly with connector is taped
together and located in a frame pocket at the driver side
rear left corner of the frame.
If the vehicle has a trailer hitch, the seven-wire harness
assembly with connector is attached to a bracket on
the hitch platform. In both cases, the seven-wire harness
has a connector and includes a 30-amp feed wire.
5-37

The seven-wire harness connector contains the following
trailer circuits:
•Light Green: Back-up Lamps (10A fuse)**
•White: Ground
•Dark Blue: Trailer Brake Signal
•Dark Green: Right Rear Stop and Turn Signal*
•Red/Black Stripe: Battery Feed (30A Fuse)
•Brown: Trailer Park Lamp Supply Voltage
(15A fuse)**
•Yellow: Left Rear Stop and Turn Signal *The four-wire harness (without connector) contains the
following circuits:
•Black: Ground
•Red/White: Battery Feed
•Dark Blue: Trailer Brake Signal
•Light Blue: CHMSL/Stoplamp Supply Voltage
* If the vehicle is a cutaway with trailer provisions, a
15 amp fuse will be shared for both left/stop trailer turn
and right/stop trailer turn signals. However, the
cutaway lighting connector will have a 10 amp fuse for
each signal.
** If the vehicle is a cutaway with trailer provisions, a
15 amp fuse will be shared for trailer park lamps
and cutaway rear lighting connector park lamps. Also, a
10 amp fuse will be shared for trailer back-up lamps
and cutaway rear lighting connector back-up lamps.
5-38

When to Check and Change Automatic
Transmission Fluid
A good time to check your automatic transmission fluid
level is when the engine oil is changed.
Change the fluid and filter at the intervals listed in
Scheduled Maintenance on page 7-3, and be sure to
use the transmission fluid listed inRecommended Fluids
and Lubricants on page 7-11.
How to Check Automatic Transmission
Fluid
Because this operation can be a little difficult, you may
choose to have this done at the dealer/retailer service
department.
If you do it yourself, be sure to follow all the instructions
here, or you could get a false reading on the dipstick.
Notice:Too much or too little uid can damage
your transmission. Too much can mean that some
of the uid could come out and fall on hot engine
parts or exhaust system parts, starting a re.
Too little uid could cause the transmission to
overheat. Be sure to get an accurate reading if
you check your transmission uid.Wait at least 30 minutes before checking the
transmission fluid level if you have been driving:
•When outside temperatures are above 32°C (90°F).
•At high speed for quite a while.
•In heavy traffic — especially in hot weather.
•While pulling a trailer.
To get the right reading, the fluid should be at
normal operating temperature, which is 82°C to 93°C
(180°F to 200°F).
Get the vehicle warmed up by driving about 24 km
(15 miles) when outside temperatures are above
10°C (50°F). If it is colder than 10°C (50°F), drive the
vehicle in D (DRIVE) until the engine temperature gage
moves and then remains steady for 10 minutes.
A cold fluid check can be made after the vehicle has
been sitting for eight hours or more with the engine off,
but this is used only as a reference. Let the engine
run at idle for five minutes if outside temperatures are
50°F (10°C) or more. If it is colder than 10°C (50°F), you
may have to idle the engine longer. Should the fluid
level be low during this cold check, you must check the
fluid hot before adding fluid. Checking the fluid hot
will give you a more accurate reading of the fluid level.
6-21