2000 GMC SIERRA wheel

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4-40
Highway Hypnosis
Is there actually such a condition as ªhighway
hypnosisº? Or is it just plain falling asleep at the
wheel? Call it highway hypnosis, lack of awareness,
or whatever.
There is something about an easy stretch of road with
the same scenery, along with the hum of the tires on the
road, the drone of the engine, and the rush of the wind
against the vehicle that can make you sleepy. Don't let it
happen to you! If it does, your vehicle can leave the
road in less than a second, and you could crash and
be injured.
What can you do about highway hypnosis? First, be
aware that it can happen.
Then here are some tips:

Make sure your vehicle is well ventilated, with a
comfortably cool interior.

Keep your eyes moving. Scan the road ahead and
to the sides. Check your mirrors and your
instruments frequently.

If you get sleepy, pull off the road into a rest, service
or parking area and take a nap, get some exercise, or
both. For safety, treat drowsiness on the highway as
an emergency.
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
driving off
-road.)

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4-43
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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4-46
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 IGN 0 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.
Two-Wheel-Drive Vehicles
Tw o-wheel-drive vehicles, should not be towed with
all four wheels on the ground. Two
-wheel-drive
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.
In rare cases when it's unavoidable that a
two
-wheel-drive vehicle is 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.
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 truck.

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4-47 Four-Wheel-Drive Vehicles
CAUTION:
Shifting the transfer case into NEUTRAL (N) 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 (N).
Use the following procedure to correctly tow your
vehicle on all four wheels:
1. Firmly set the parking brake.
2. Shift an automatic transmission to PARK (P), or a
manual transmission to FIRST (1).
3. Securely attach the vehicle being towed to the
tow vehicle.
4. Shift the transfer case to NEUTRAL (N). See
ªFour
-Wheel Driveº in the Index for the proper
procedure to select the neutral position for
your vehicle.
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 as long
as the IGN 0 fuse is removed. Unlocking the steering
column will allow the proper movement of the front
wheels and tires during towing.

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4-51 Front Axle Reserve Capacity
This is the difference between your front GAWR and the
front axle weight of your truck with full fuel and
passengers. It is the amount of weight you can add to
your front axle before reaching your front GAWR.
The front axle reserve
capacity for your vehicle
can be found in the lower
right corner of the
tire/certification label, as
shown in this example.In order to calculate the amount of weight any front
accessory is adding to the front axle, use the
following formula.
(W x (A+W.B.)) / W.B.= Weight the accessory is adding
to the front axle
Where: W= Weight of added accessory
A= Distance that the accessory is
in front of the front axle
W.B.= Vehicle Wheelbase

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4-52
For example, adding a 700 lbs. (318 kg) snow plow
adds more than 700 lbs. (318 kg) to the front axle.
Using the formula, if the snow plow is 4 ft. (122 cm)
in front of the front axle and the wheel base is 10 ft.
(305 cm), then:
W= 700 lbs. (318 kg), A= 4 ft. (122 cm) and W.B.=
10 ft. (305 cm)
(W x (A+W.B.)) / W.B. = (700 x (4ft. + 10 ft.)) /
10 ft. = 980 lbs.
So, if your truck's front axle reserve capacity is more
than 980 lbs. (445 kg), you could add this snow plow
without exceeding the front GAWR.
You can add heavier equipment on the front of the
vehicle if you compensate for it by carrying fewer
passengers, less cargo or by positioning cargo more
towards the rear. This has the effect of reducing the load
on the front. However, the front GAWR, rear GAWR
and the GVWR must never be exceeded.Total Vehicle Reserve Capacity
This is the difference between your GVWR and the
weight of your truck with full fuel and passengers. It is
the amount of weight you can add to your vehicle before
reaching your GVWR.
The reserve capacity numbers are intended as a guide
when selecting the amount of equipment or cargo your
truck can carry. If you are unsure of your truck's front,
rear or total weight, go to a weigh station and weigh
your vehicle. Your dealer can help you with this.
Truck-Camper Loading Information
This label is inside your glove box. It will tell you if
your vehicle can carry a slide
-in camper, how much of a
load your vehicle can carry, and how to correctly spread
out your load. Also, it will help you match the right
slide
-in camper to your vehicle.
When you carry a slide
-in camper, the total cargo load
of your vehicle is the weight of the camper, plus

everything else added to the camper after it left
the factory,

everything in the camper and

all the people inside.

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4-54
Your dealer can help you make a good vehicle-camper
match. He'll also help you determine your CWR.
After you've loaded your vehicle and camper, drive to a
weigh station and weigh the front and rear wheels
separately. This will tell you the loads on your axles.
The loads on the front and rear axles shouldn't be more
than either of the GAWRs. The total of the axle loads
should not be more than the GVWR.
Open your driver's door and look at the
Certification/Tire label to find out your GAWR
and GVWR.
If you've gone over your weight ratings, move or take
out some things until all the weight falls below the
ratings. Of course, you should always tie down any
loose items when you load your vehicle or camper.
When you install and load your slide
-in camper, check
the manufacturer's instructions.
If you want more information on curb weights, cargo
weights, Cargo Weight Rating and the correct center of
gravity zone for your vehicle, your dealer can help you.
Just ask for a copy of ªConsumer Information,
Truck
-Camper Loading.º
Trailer Recommendations
You must subtract your hitch loads from the CWR for
your vehicle. Weigh your vehicle with the trailer
attached, so that you won't go over the GVWR or
GAWR. If you are using a weight
-distributing hitch,
weigh the vehicle without the equalizer bars in place.
You'll get the best performance if you spread out the
weight of your load the right way, and if you choose the
correct hitch and trailer brakes.
For more information, see ªTrailer Towingº in
the Index.
Camper Wiring Harness
(If Equipped)
If your vehicle is equipped with a camper wiring harness
see ªTrailer Wiring Harnessº in the Index for
further information.

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4-58 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. And, it can also depend on any
special equipment that you have on your vehicle.
Use one of the following charts to determine how much
your vehicle can weigh, based upon your vehicle model
and options.
Maximum trailer weight is calculated assuming the
driver and one passenger are 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.
Above the 5,000 lbs. (2 268 kg) trailer rating, the
handling/trailering suspension is required on C
-1500
models and the handling/trailering or off
-road
suspension is required on K
-1500 models. The engine
oil cooler is required on C/K
-2500 models with the
VORTEC 6000 engine. Refer to the Trailering Guide for
oil cooler recommendations.C
-1500 (2WD)*
Engine (Trans.) Axle
RatioMax. Trailer Wt.
4300 V6 (Auto) 3.08 4,000 lbs. (1 814 kg)
3.42 4,500 lbs. (2 041 kg)
3.73 5,000 lbs. (2 268 kg)
4300 V6 (Manual) 3.08 3,500 lbs. (1 588 kg)
3.42 4,000 lbs. (1 814 kg)
4800 V8 (Auto) 3.42 6,000 lbs. (2 722 kg)
3.73 7,000 lbs. (3 175 kg)
4800 V8 (Manual) 3.42 4,000 lbs. (1 814 kg)
3.73 5,000 lbs. (2 268 kg)
5300 V8 3.42 7,000 lbs. (3 175 kg)
3.73 8,200 lbs. (3 720 kg)
* Weight
-distributing hitch tongue weight 10% to 15%
of hitch pulling weight 1,000 lb. (454 kg) maximum.
Fifth
-wheel hitch tongue weight 15% to 25% of hitch
pulling weight 1,500 lb (680 kg) maximum.