2003 GMC SONOMA four wheel drive

Off-Road Driving with Your
Four-Wheel-Drive Vehicle
This off-road guide is for vehicles that have four-wheel
drive.
Also, seeAnti-Lock BrakesunderBraking on page 4-5.
If your vehicle doesn’t have four-wheel drive, you
shouldn’t drive off-road unless you’re on a level, solid
surface.
Off-road driving can be great fun. But it does have
some denite hazards. The greatest of these is
the terrain itself.
'Off-roading' means you’ve left the great North American
road system behind. Traffic lanes aren’t marked.
Curves aren’t banked. There are no road signs.
Surfaces can be slippery, rough, uphill or downhill.
In short, you’ve gone right back to nature.
Off-road driving involves some new skills. And that’s
why it’s very important that you read this guide.
You’llnd many driving tips and suggestions. These will
help make your off-road driving safer and more
enjoyable.
Before You Go Off-Roading
There are some things to do before you go out. For
example, be sure to have all necessary maintenance
and service work done. Check to make sure all
underbody shields (if so equipped) are properly
attached. Be sure you read all the information about
your four-wheel-drive vehicle in this manual. Is
there enough fuel? Is the spare tire fully inated?
Are theuid levels up where they should be? What are
the local laws that apply to off-roading where you’ll
be driving? If you don’t know, you should check with law
enforcement people in the area. Will you be on
someone’s private land? If so, be sure to get the
necessary permission.
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If you drive regularly in steep country, or if you’re
planning to visit there, here are some tips that can make
your trips safer and more enjoyable. SeeOff-Road
Driving with Your Four-Wheel-Drive Vehicle on
page 4-13for information about driving off-road.
Keep your vehicle in good shape. Check alluid
levels and also the brakes, tires, cooling system
and transmission. These parts can work hard
on mountain roads.
Know how to go down hills. The most important
thing to know is this: let your engine do some of
the slowing down. Shift to a lower gear when you
go down a steep or long hill.
{CAUTION:
If you don’t shift down, your brakes could get
so hot that they wouldn’t work well. You would
then have poor braking or even none going
down a hill. You could crash. Shift down to let
your engine assist your brakes on a steep
downhill slope.
{CAUTION:
Coasting downhill in NEUTRAL (N) or with the
ignition off is dangerous. Your brakes will have
to do all the work of slowing down. They
couldget so hot that they wouldn’t work well.
You would then have poor braking or even
none going down a hill. You could crash.
Always have your engine running and your
vehicle in gear when you go downhill.
Know how to go uphill. You may want to shift down to
a lower gear. The lower gears help cool your engine
and transmission, and you can climb the hill better.
Stay in your own lane when driving on two-lane
roads in hills or mountains. Don’t swing wide or cut
across the center of the road. Drive at speeds that let
you stay in your own lane.
As you go over the top of a hill, be alert. There could
be something in your lane, like a stalled car or an
accident.
You may see highway signs on mountains that warn
of special problems. Examples are long grades,
passing or no-passing zones, a falling rocks area or
winding roads. Be alert to these and take appropriate
action.
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If You Are Stuck: In Sand, Mud,
Ice or Snow
In order to free your vehicle when it is stuck, you will need
to spin the wheels, but you don’t want to spin your wheels
too fast. The method known as“rocking”can help you get
out when you’re stuck, but you must use caution.
{CAUTION:
If you let your tires spin at high speed, they
can explode, and you or others could be
injured. And, the transmission or other parts of
the vehicle can overheat. That could cause an
engine compartment fire or other damage.
When you’re stuck, spin the wheels as little as
possible. Don’t spin the wheels above 35 mph
(55 km/h) as shown on the speedometer.
Notice:Spinning your wheels can destroy parts of
your vehicle as well as the tires. If you spin the
wheels too fast while shifting your transmission
back and forth, you can destroy your transmission.
For information about using tire chains on your
vehicle, seeTire Chains on page 5-66.
Rocking Your Vehicle To Get It Out
First, turn your steering wheel left and right. That will
clear the area around your front wheels. If you have a
four-wheel-drive vehicle, shift into 4HI. Then shift
back and forth between REVERSE (R) and a forward
gear (or with a manual transmission, between FIRST (1)
or SECOND (2) and REVERSE (R)), spinning the
wheels as little as possible. Release the accelerator
pedal while you shift, and press lightly on the accelerator
pedal when the transmission is in gear. By slowly
spinning your wheels in the forward and reverse
directions, you will cause a rocking motion that may free
your vehicle. If that doesn’t get you out after a few
tries, you may need to be towed out. Or, you can use
your recovery hooks if your vehicle has them. If you do
need to be towed out, seeTowing Your Vehicle on
page 4-42.
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Dinghy Towing
Notice:Towing your vehicle with all four wheels on
the ground will damage drivetrain components.Your two-wheel-drive vehicle should not be towed with
all four wheels on the ground. Your transmission
has no provision for internal lubrication while being
towed. To properly to your vehicle, it should be placed
on a platform trailer with all four wheels off the
ground. Towing with all four wheels on the ground
should be avoided.
In rare cases when it’s unavoidable and your vehicle
must be towed with all four wheels on the ground,
the propeller shaft to axle yoke orientation should be
marked and the propeller shaft removed following
the applicable service manual removal/installation
procedure. SeeService Publications Ordering
Information on page 7-9.
Dust or dirt can enter the back of the transmission
through the opening created by removing the propeller
shaft if proper protection is not provided. Also, check
the transmissionuid level before driving the vehicle. Two-Wheel Drive Vehicles Only
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When towing your vehicle, turn the ignition to OFF.
To prevent your battery from draining while towing,
remove the RDO BATT and CLSTR fuses from
the instrument panel fuse block. Be sure to replace the
fuse when you reach your destination. SeeFuses
and Circuit Breakers on page 5-89. Be sure to use the
proper towing equipment designed for recreational
vehicle towing. Follow the instructions for the towing
equipment.
{CAUTION:
Shifting a four-wheel-drive vehicle’s transfer
case into NEUTRAL can cause your vehicle to
roll even if the transmission is in Park (P) for
an automatic transmission, or if your vehicle is
in gear, for a manual transmission. You or
others could be injured. Make sure the parking
brake isfirmly set before you shift the transfer
case to NEUTRAL.
If your vehicle has four-wheel-drive it cannot be dinghy
towed. A four-wheel-drive vehicle must be towed by
atbed.
Dolly Towing
Notice:Towing your vehicle with all four wheels on
the ground will damage drivetrain components.
Your two-wheel-drive vehicle should not be towed with
two wheels on the ground. Your transmission has no
provision for internal lubrication while being towed.
To properly tow your vehicle, it should be placed on a
platform trailer with all four wheels off the ground. Towing
with all four wheels on the ground should be avoided.Two-Wheel-Drive Vehicles Only
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In rare cases when it’s unavoidable and your vehicle
must be towed with two wheels on the ground, the
propeller shaft to axle yoke orientation should be marked
and the propeller shaft removed following the applicable
service manual removal/installation procedure. See
Service Publications Ordering Information on page 7-9.
Dust or dirt can enter the back of the transmission
through the opening created by removing the propeller
shaft if proper protection is not provided. Also, check
the transmissionuid level before driving the vehicle.
Use the following steps to dolly tow your vehicle:
1. Put the front wheels on a dolly.
2. Put the vehicle in PARK (P).
3. Set the parking brake and then remove the key.
4. Disconnect the propshaft as described above.
5. Clamp the steering wheel in a straight-ahead
position with a clamping device designed for towing.
6. Release the parking brake.Be sure to use the proper towing equipment designed
for recreational vehicle towing. Follow the instructions for
the towing equipment.
{CAUTION:
Shifting a four-wheel-drive vehicle’s transfer
case into NEUTRAL can cause your vehicle to
roll even if the transmission is in Park (P) for
an automatic transmission, or if your vehicle is
in gear, for a manual transmission. You or
others could be injured. Make sure the parking
brake isfirmly set before you shift the transfer
case to NEUTRAL.
If your vehicle has four-wheel-drive it cannot be dolly
towed. A four-wheel-drive vehicle must be towed
byatbed.
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{CAUTION:
Do not load your vehicle any heavier than the
GVWR, or either the maximum front or rear
GAWR. If you do, parts on your vehicle can
break, and it can change the way your vehicle
handles. These could cause you to lose
control and crash. Also, overloading can
shorten the life of your vehicle.
Using heavier suspension components to get added
durability might not change your weight ratings. Ask your
dealer to help you load your vehicle the right way.
Notice:Your warranty does not cover parts
or components that fail because of overloading.
If you put things inside your vehicle—like suitcases,
tools, packages, or anything else—they will go as fast
as the vehicle goes. If you have to stop or turn
quickly, or if there is a crash, they’ll keep going.
{CAUTION:
Things you put inside your vehicle can strike
and injure people in a sudden stop or turn,
or in a crash.
•Put things in the trunk of your vehicle. In a
trunk, put them as far forward as you can.
Try to spread the weight evenly.
•Never stack heavier things, like suitcases,
inside the vehicle so that some of them
are above the tops of the seats.
•Don’t leave an unsecured child restraint in
your vehicle.
•When you carry something inside the
vehicle, secure it whenever you can.
•Don’t leave a seat folded down unless you
need to.
There’s also important loading information for off-road
driving in this manual. See“Loading Your Vehicle
for Off-Road Driving″underOff-Road Driving with Your
Four-Wheel-Drive Vehicle on page 4-13.
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Driving On Grades
Reduce speed and shift to a lower gear before you start
down a long or steep downgrade. If you don’t shift
down, you might have to use your brakes so much that
they would get hot and no longer work well.
If you have an automatic transmission, you should use
THIRD (3) when towing a trailer. Operating your
vehicle in THIRD (3) when towing a trailer will minimize
heat buildup and extend the life of your transmission.
Or, if you have a manual transmission, it’s better not to
use FIFTH (5). Just drive in FOURTH (4) (or, as you
need to, a lower gear).
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 you turn your
engine off immediately after towing at high altitude
on steep uphill grades, your 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 PARK (P)
(or the manual transmission out of gear and the parking
brake applied) for a few minutes before turning the
engine off. If you do get the overheat warning,
seeEngine Overheating on page 5-28.
Parking on Hills
{CAUTION:
You really should not park your vehicle, with a
trailer attached, on a hill. If something goes
wrong, your rig could start to move. People
can be injured, and both your vehicle and the
trailer can be damaged.
But if you ever have to park your rig on a hill, here’s
how to do it:
1. Apply your regular brakes, but don’t shift into
PARK (P) yet, or into gear for a manual
transmission. When parking uphill, turn your wheels
away from the curb. When parking downhill, turn
your wheels into the curb.
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.
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