1999 GMC JIMMY Index

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4-35
Hill and Mountain Roads
Driving on steep hills or mountains is different from
driving in flat or rolling terrain.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. (See ªOff
-Road
Drivingº in the Index for information about d
riving off
-road.)

Keep your vehicle in good shape. Check all fluid
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.

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4-38
What's the worst time for this? ªWet ice.º Very cold
snow or ice can be slick and hard to drive on. But wet
ice can be even more trouble because it may offer the
least traction of all. You can get wet ice when it's about
freezing (32F; 0C) and freezing rain begins to fall.
Try to avoid driving on wet ice until salt and sand crews
can get there.Whatever the condition
-- smooth ice, packed, blowing
or loose snow
-- drive with caution.
Accelerate gently. Try not to break the fragile traction. If
you accelerate too fast, the drive wheels will spin and
polish the surface under the tires even more.
Your anti
-lock brakes improve your vehicle's stability
when you make a hard stop on a slippery road. Even
though you have an anti
-lock braking system, you'll
want to begin stopping sooner than you would on dry
pavement. See ªAnti
-Lockº in the Index.

Allow greater following distance on any
slippery road.

Watch for slippery spots. The road might be fine
until you hit a spot that's covered with ice. On an
otherwise clear road, ice patches may appear in
shaded areas where the sun can't reach: around
clumps of trees, behind buildings or under bridges.
Sometimes the surface of a curve or an overpass may
remain icy when the surrounding roads are clear. If
you see a patch of ice ahead of you, brake before you
are on it. Try not to brake while you're actually on
the ice, and avoid sudden steering maneuvers.

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4-40
CAUTION:
Snow can trap exhaust gases under your vehicle.
This can cause deadly CO (carbon monoxide) gas
to get inside. CO could overcome you and kill
you. You can't see it or smell it, so you might not
know it is in your vehicle. Clear away snow from
around the base of your vehicle, especially any
that is blocking your exhaust pipe. And check
around again from time to time to be sure snow
doesn't collect there.
Open a window just a little on the side of the
vehicle that's away from the wind. This will help
keep CO out.
Run your engine only as long as you must. This saves
fuel. When you run the engine, make it go a little faster
than just idle. That is, push the accelerator slightly. This
uses less fuel for the heat that you get and it keeps the
battery charged. You will need a well
-charged battery to
restart the vehicle, and possibly for signaling later on
with your headlamps. Let the heater run for a while.Then, shut the engine off and close the window almost
all the way to preserve the heat. Start the engine again
and repeat this only when you feel really uncomfortable
from the cold. But do it as little as possible. Preserve the
fuel as long as you can. To help keep warm, you can get
out of the vehicle and do some fairly vigorous exercises
every half hour or so until help comes.
Recreational Vehicle Towing
There may be times when you want to tow your vehicle
behind another vehicle for use at your destination. Be
sure to use the proper towing equipment designed for
recreational vehicle towing. Follow the instructions for
the towing equipment.
When towing your vehicle, turn the ignition to OFF.
To prevent your battery from draining while towing,
remove the RDO BATT fuse from the instrument panel
fuse block. Be sure to replace the fuse when you reach
your destination. See ªFuses and Circuit Breakersº in
the Index.

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4-41 Two-Wheel Drive Vehicles and Vehicles
with the Electronic Shift Transfer Case
Tw o-wheel-drive vehicles and vehicles with the Electronic
Shift Transfer Case should not be towed with all four wheels
on the ground. These transmissions have no provisions for
internal lubrication while being towed. To properly tow these
vehicles, they 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 has to
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. See ªService and
Owner Publicationsº in the Index.
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 transmission fluid level before driving the vehicle.
Four-Wheel-Drive Vehicles
(Automatic Transfer Case)
Use the following procedure to correctly tow your
vehicle on all four wheels:
1. Firmly set the parking brake.
2. Place the transmission in PARK (P).
3. Securely attach the vehicle being towed to the
tow vehicle.
4. With the engine running, shift the transfer case to
NEUTRAL. See ªFour
-Wheel Driveº in the Index
for the proper procedure to select the neutral position
for your vehicle.

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CAUTION:
Shifting the 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 is firmly set before
you shift the transfer case into NEUTRAL.
See ªFour
-Wheel Drive (Automatic Transfer
Case)º in the Index.
5. Release the parking brake only after the vehicle
being towed is firmly attached to the towing vehicle.
6. Turn the ignition to OFF. The OFF position unlocks
the steering column and reduces battery drain.
Unlocking the steering column will allow the proper
movement of the front wheels and tires
during towing.
Loading Your Vehicle
The Certification/Tire label is found on the driver's door
edge, above the door latch. The label shows the size of
your original tires and the inflation pressures needed to
obtain the gross weight capacity of your vehicle. This is
called the Gross Vehicle Weight Rating (GVWR). The
GVWR includes the weight of the vehicle, all occupants,
fuel, cargo and trailer tongue weight, if pulling a trailer.

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4-44
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 cargo area of your vehicle.
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 ªLoading Your Vehicle for
Off
-Road Drivingº in the Index.
Payload
The payload capacity is shown on the Certification/Tire
label. This is the maximum load capacity that your
vehicle can carry. Be sure to include the weight of the
occupants as part of your load. If you added any
accessories or equipment after your vehicle left the
factory, remember to subtract the weight of these things
from the payload. Your dealer can help you with this.
Add-On Equipment
When you carry removable items, you may need to put a
limit on how many people you carry inside your vehicle.
Be sure to weigh your vehicle before you buy and install
the new equipment.
NOTICE:
Your warranty doesn't cover parts or
components that fail because of overloading.

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4-47
Tow/Haul Mode (V6 Engine, Automatic
Transmission Equipped Models) (If Equipped)
The Tow/Haul Mode is a feature that assists when
pulling a heavy trailer. The purpose of the Tow/Haul
Mode is:

Reduce the frequency of shifts when pulling a
heavy trailer.

Provide the same shift feel when pulling a heavy
trailer as when the vehicle is unloaded.

Reduce the need to change throttle position when
pulling a heavy trailer.
This feature is turned on or off by pressing a button on
the floor console. When the feature is on, a light on the
instrument panel will illuminate to indicate that the
Tow/Haul Mode has been selected. See ªTow/Haul
Mode Lightº in the Index. The Tow/Haul Mode is
automatically turned off each time the vehicle is started.
The Tow/Haul Mode is most effective when the vehicle
and trailer combined weight is at least 75% of the Gross
Vehicle Weight Rating (GVWR) and the maximum
trailer weight rating for the vehicle. See ªGross Vehicle
Weight Ratingº and ªTrailer Weightº in the Index.The Tow/Haul Mode for hauling a heavy trailer is most
useful under the following conditions

When driving through hilly terrain at speeds below
55 mph (88 km/h).

When driving in low speed or stop and go traffic
below 55 mph (88 km/h).

When driving in parking lots.
Use the Tow/Haul Mode instead of the previous
recommendation to shift to THIRD (3) gear to improve
fuel economy at highway speeds and shift performance
at lower speeds. Operating in the Tow/Haul Mode when
not pulling a heavy trailer will not cause damage to the
vehicle, but you may experience reduced fuel economy
and undesirable performance from the engine and
transmission. The Tow/Haul Mode should be used only
when pulling a heavy trailer.

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4-49 Weight of the Trailer Tongue
The tongue load (A) of any trailer is an important
weight to measure because it affects the total or gross
weight of your vehicle. The Gross Vehicle Weight
(GVW) includes the curb weight of the vehicle, any
cargo you may carry in it, and the people who will be
riding in the vehicle. And if you will tow a trailer, you
must add the tongue load to the GVW because your
vehicle will be carrying that weight, too. See ªLoading
Your Vehicleº in the Index for more information about
your vehicle's maximum load capacity.
If you're using a weight-carrying hitch, the trailer
tongue (A) should weigh 10 percent of the total loaded
trailer weight (B). If you're using a weight
-distributing
hitch, the trailer tongue (A) should weigh 12 percent of
the total loaded trailer weight (B).
After you've loaded your trailer, weigh the trailer and
then the tongue, separately, to see if the weights are
proper. If they aren't, you may be able to get them right
simply by moving some items around in the trailer.
Total Weight on Your Vehicle's Tires
Be sure your vehicle's tires are inflated to the upper
limit for cold tires. You'll find these numbers on the
Certification/Tire label on the driver's door edge, above
the door latch, or see ªTire Loadingº in the Index. Then
be sure you don't go over the GVW limit for your
vehicle, including the weight of the trailer tongue.