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AUTOMATIC OVERDRIVE (): This position is
for normal driving. If you need more power for passing,
and you're:
Going less than about 35 mph (56 km/h), push your
accelerator pedal about halfway down.
Going about 35 mph (56 km/h) or more, push the
accelerator all the way down.
You'll shift down to the next gear and have more power.
AUTOMATIC OVERDRIVE () can be used when
towing a trailer, carrying a heavy load, driving on steep
hills or for off
-road driving. You may want to shift the
transmission to THIRD (3) or, if necessary, a lower gear
selection if the transmission shifts too often.
THIRD (3): This position is also used for normal
driving, however it offers more power and lower fuel
economy than AUTOMATIC OVERDRIVE ().
SECOND (2): This position gives you more power, but
lower fuel economy. You can use SECOND (2) on hills.
It can help control your speed as you go down steep
mountain roads, but then you would also want to use
your brakes off and on.If you manually select SECOND (2), the transmission
will drive in second gear. You may use this feature
for reducing torque to the rear wheels when you are
trying to start your vehicle from a stop on slippery
road surfaces.
FIRST (1): This position gives you even more power,
but lower fuel economy than SECOND (2). You can use
it on very steep hills, or in deep snow or mud. If the
selector lever is put in FIRST (1) while the vehicle is
moving forward, the transmission won't shift into first
gear until the vehicle is going slowly enough.
NOTICE:
If your rear wheels can't rotate, don't try to
drive. This might happen if you were stuck in
very deep sand or mud or were up against a solid
object. You could damage your transmission.
Also, if you stop when going uphill, don't hold
your vehicle there with only the accelerator
pedal. This could overheat and damage the
transmission. Use your brakes or shift into
PARK (P) to hold your vehicle in position
on a hill.
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5-28
Front Position Rear Position
7. Lower the vehicle by rotating the ratchet and wheel
wrench counterclockwise. Lower the jack completely.
8. Tighten the nuts
firmly in a crisscross
sequence as shown
by rotating the wheel
wrench clockwise.
CAUTION:
Incorrect wheel nuts or improperly tightened
wheel nuts can cause the wheel to become loose
and even come off. This could lead to an accident.
Be sure to use the correct wheel nuts. If you have
to replace them, be sure to get new GM original
equipment wheel nuts.
Stop somewhere as soon as you can and have the
nuts tightened with a torque wrench to the
proper torque. See ªCapacities and
Specificationsº in the Index.
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5-29
NOTICE:
Improperly tightened wheel nuts can lead to
brake pulsation and rotor damage. To avoid
expensive brake repairs, evenly tighten the wheel
nuts in the proper sequence and to the proper
torque specification.
9. Put the wheel trim back on. For vehicles with plastic
wheel nut caps, tighten the caps until they are
finger
-tight, then tighten them an additional one-half
of a turn with the ratchet and wheel wrench.
Storing a Flat or Spare Tire and Tools
CAUTION:
Storing a jack, a tire or other equipment in the
passenger compartment of the vehicle could
cause injury. In a sudden stop or collision, loose
equipment could strike someone. Store all these
in the proper place.
Store the flat tire where the spare tire was stored.
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6-37
NOTICE:
Continuing to drive with worn-out brake pads
could result in costly brake repair.
Some driving conditions or climates may cause a brake
squeal when the brakes are first applied or lightly
applied. This does not mean something is wrong with
your brakes.
Properly torqued wheel nuts are necessary to help
prevent brake pulsation. When tires are rotated, inspect
brake pads for wear and evenly torque wheel nuts in the
proper sequence to GM specifications.
If you have rear drum brakes, they don't have wear
indicators, but if you ever hear a rear brake rubbing
noise, have the rear brake linings inspected immediately.
Also, the rear brake drums should be removed and
inspected each time the tires are removed for rotation or
changing. When you have the front brake pads replaced,
have the rear brakes inspected, too.Brake linings should always be replaced as complete
axle sets.
See ªBrake System Inspectionº in Section 7
of this manual under Part C ªPeriodic
Maintenance Inspections.ºBrake Pedal Travel
See your dealer if the brake pedal does not return to
normal height, or if there is a rapid increase in pedal
travel. This could be a sign of brake trouble.
Brake Adjustment
Every time you make a brake stop, your disc brakes
adjust for wear.
If your brake pedal goes down farther than normal, your
rear drum brakes may need adjustment. Adjust them by
backing up and firmly applying the brakes a few times.
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6-53
If your vehicle has dual rear wheels and the load range
and tread design for your front tires is the same as your
rear tires, always use one of the correct rotation patterns
shown here when rotating your tires.
If your vehicle has dual rear
wheels and the load range
or tread design for your
front tires is different from
your rear tires, always use
the correct rotation pattern
shown here when rotating
your tires.
The dual tires are rotated as a pair, and the inside rear
tires become the outside rear tires.
When you install dual wheels, be sure the vent holes in
the inner and outer wheels on each side are lined up.
After the tires have been rotated, adjust the front and
rear inflation pressures as shown on the
Certification/Tire label. Make certain that all wheel nuts
are properly tightened. See ªWheel Nut Torqueº in
the Index.
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6-55 Dual Tire Operation
When the vehicle is new, or whenever a wheel, wheel
bolt or wheel nut is replaced, check the wheel nut torque
after 100, 1,000 and 6,000 miles (160, 1 600 and
10 000 km) of driving. For proper torque, see ªWheel
Nut Torqueº in the Index.
The outer tire on a dual wheel setup generally wears
faster than the inner tire. Your tires will wear more
evenly and last longer if you rotate the tires periodically.
If you're going to be doing a lot of driving on
high
-crown roads, you can reduce tire wear by adding
5 psi (35 kPa) to the tire pressure in the outer tires.
Be sure to return to the recommended pressures when no
longer driving under those conditions. See ªChanging a
Flat Tireº in the Index for more information.
CAUTION:
If you operate your vehicle with a tire that is
badly underinflated, the tire can overheat. An
overheated tire can lose air suddenly or catch
fire. You or others could be injured. Be sure
all tires (including the spare, if any) are
properly inflated.
Buying New Tires
To find out what kind and size of tires you need, look at
the Certification/Tire label.
The tires installed on your vehicle when it was new had
a Tire Performance Criteria Specification (TPC Spec)
number on each tire's sidewall. When you get new tires,
get ones with that same TPC Spec number. That way
your vehicle will continue to have tires that are designed
to give proper endurance, handling, speed rating,
traction, ride and other things during normal service on
your vehicle. If your tires have an all
-season tread
design, the TPC number will be followed by an ªMSº
(for mud and snow).
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NOTICE:
The wrong wheel can also cause problems with
bearing life, brake cooling, speedometer or
odometer calibration, headlamp aim, bumper
height, vehicle ground clearance and tire or tire
chain clearance to the body and chassis.
Whenever a wheel, wheel bolt or wheel nut is replaced
on a dual wheel setup, check the wheel nut torque after
100, 1,000 and 6,000 miles (160, 1 600 and 10 000 km)
of driving. For proper torque, see ªWheel Nut Torqueº
in the Index.
See ªChanging a Flat Tireº in the Index for
more information.Used Replacement Wheels
CAUTION:
Putting a used wheel on your vehicle is
dangerous. You can't know how it's been used or
how far it's been driven. It could fail suddenly
and cause an accident. If you have to replace a
wheel, use a new GM original equipment wheel.
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Capacities and Specifications
Please refer to ªRecommended Fluids and Lubricantsº in the Index for more information.
Engine Type VIN Code Spark Plug Gap
ªVORTECº 5000 V8 M 0.06 inches (1.52 mm)
ªVORTECº 5700 V8 R 0.06 inches (1.52 mm)
ªVORTECº 7400 V8 J 0.06 inches (1.52 mm)
Wheels and Tires
Model Description Torque
C/K 1500 5 bolts (14 mm)
140 lb
-ft (190 N´m)
C/K 1500 and C/K 2500 6 bolts (14 mm)
140 lb
-ft (190 N´m)
C/K 2500 (w/C6P) 8 bolts (14 mm)
140 lb
-ft (190 N´m)
C/K 3500 (Single Rear Wheels) 8 bolts (14 mm)
140 lb
-ft (190 N´m)
C/K 3500 (Dual Rear Wheels) 8 bolts (14 mm)
140 lb
-ft (190 N´m)
C 3500 HD Front 5 bolts (5/8 in.)
175 lb
-ft (240 N´m)
C 3500 HD Rear 10 bolts (5/8 in.)
175 lb
-ft (240 N´m)
Tire Pressure See the Certification/Tire label on the rear edge of the driver's door
or the incomplete vehicle document in the cab.