change time GMC SIERRA 1999 User Guide

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4-49
Towing a Trailer
CAUTION:
If you don't use the correct equipment and drive
properly, you can lose control when you pull a
trailer. For example, if the trailer is too heavy, the
brakes may not work well
-- or even at all. You
and your passengers could be seriously injured.
Pull a trailer only if you have followed all the
steps in this section. Ask your dealer for advice
and information about towing a trailer with
your vehicle.
NOTICE:
Pulling a trailer improperly can damage your
vehicle and result in costly repairs not covered by
your warranty. To pull a trailer correctly, follow
the advice in this part, and see your dealer for
important information about towing a trailer
with your vehicle.
Your vehicle may be able to tow a trailer. To identify
what the vehicle trailering capacity is for your vehicle,
you should read the information in ªWeight of the
Trailerº that appears later in this section.
If yours was built with trailering options, as many are,
it's ready for heavier trailers. But trailering is different
than just driving your vehicle by itself. Trailering means
changes in handling, durability and fuel economy.
Successful, safe trailering takes correct equipment, and
it has to be used properly.
That's the reason for this part. In it are many
time
-tested, important trailering tips and safety rules.
Many of these are important for your safety and that of
your passengers. So please read this section carefully
before you pull a trailer.

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5-27
CAUTION:
Rust or dirt on the wheel, or on the parts to
which it is fastened, can make the wheel nuts
become loose after a time. The wheel could come
off and cause an accident. When you change a
wheel, remove any rust or dirt from the places
where the wheel attaches to the vehicle. In an
emergency, you can use a cloth or a paper towel
to do this; but be sure to use a scraper or wire
brush later, if you need to, to get all the rust
or dirt off.
CAUTION:
Never use oil or grease on studs or nuts. If you
do, the nuts might come loose. Your wheel could
fall off, causing a serious accident.
6. Replace the wheel
nuts with the
rounded end of the
nuts toward the
wheel. Tighten
each wheel nut by
hand using the
wheel wrench until
the wheel is held
against the hub.

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6-20
Automatic Transmission Fluid
If your vehicle has a diesel engine, see ªAutomatic
Transmission Fluidº in the Diesel Supplement.
When to Check and Change
A good time to check your automatic transmission fluid
level is when the engine oil is changed.
Change both the fluid and filter every 50,000 miles
(83 000 km) if the vehicle's GVWR is over 8,600 or
if the vehicle is mainly driven under one or more of
these conditions:

In heavy city traffic where the outside temperature
regularly reaches 90F (32C) or higher.

In hilly or mountainous terrain.

When doing frequent trailer towing.

Uses such as found in taxi, police or delivery service.
If your vehicle's GVWR is not over 8,600 and you
do not use your vehicle under any of these conditions,
change the fluid and filter every 100,000 miles
(166 000 km).
See ªScheduled Maintenance Servicesº in the Index.
How to Check
Because this operation can be a little difficult, you may
choose to have this done at the GM 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 fluid can damage your
transmission. Too much can mean that some of
the fluid could come out and fall on hot engine
parts or exhaust system parts, starting a fire.
Be sure to get an accurate reading if you check
your transmission fluid.
Wait at least 30 minutes before checking the
transmission fluid level if you have been driving:

When outside temperatures are above 90F (32C).

At high speed for quite a while.

In heavy traffic
-- especially in hot weather.

While pulling a trailer.

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6-23 How to Add Fluid
Refer to the Maintenance Schedule to determine what
kind of transmission fluid to use. See ªRecommended
Fluids and Lubricantsº in the Index.
Add fluid only after checking the transmission fluid
while it is hot. (A cold check is used only as a
reference.) If the fluid level is low, add only enough of
the proper fluid to bring the level up to the HOT area for
a hot check. It doesn't take much fluid, generally less
than one pint (0.5 L). Don't overfill.
NOTICE:
We recommend you use only fluid labeled
DEXRON-III, because fluid with that label is
made especially for your automatic transmission.
Damage caused by fluid other than DEXRON
-III
is not covered by your new vehicle warranty.

After adding fluid, recheck the fluid level as
described under ªHow to Check.º

When the correct fluid level is obtained, push the
dipstick back in all the way; then flip the handle
down to lock the dipstick in place.
Manual Transmission Fluid
When to Check
A good time to have it checked is when the engine oil
is changed. However, the fluid in your manual
transmission doesn't require changing.
How to Check
Because this operation can be a little difficult, you may
choose to have this done at your GM dealership
Service Department.
If you do it yourself, be sure to follow all the
instructions here, or you could get a false reading.
NOTICE:
Too much or too little fluid can damage your
transmission. Too much can mean that some of
the fluid could come out and fall on hot engine
parts or exhaust system parts, starting a fire. Be
sure to get an accurate reading if you check your
transmission fluid.

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6-26 C3 (3500 HD) Trucks Equipped with Dana
Rear Axle
Additional rear axle scheduled maintenance is required
on 3500 HD models equipped with Dana rear axles
when they are driven under the following conditions:

Extreme loading (at or near GVWR) or trailer
towing, and:

Operation above 45 mph (70 km/h) for extended
periods of time
Vehicles used in any of these conditions require the
rear axle lubricant be changed every 30,000 miles
(50 000 km). Fluid capacity is 4.12 quarts (3.9 L).
Four-Wheel Drive
Most lubricant checks in this section also apply to
four
-wheel-drive vehicles. However, they have two
additional systems that need lubrication.
Transfer Case
When to Check Lubricant
Refer to the Maintenance Schedule to determine how
often to check the lubricant. See ªPeriodic Maintenance
Inspectionsº in the Index.How to Check Lubricant
If the level is below the bottom of the filler plug hole,
you'll need to add some lubricant. Add enough lubricant
to raise the level to the bottom of the filler plug hole.
Use care not to overtighten the plug.
What to Use
Refer to the Maintenance Schedule to determine what
kind of lubricant to use. See ªRecommended Fluids and
Lubricantsº in the Index.

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6-38 Replacing Brake System Parts
The braking system on a vehicle is complex. Its many
parts have to be of top quality and work well together
if the vehicle is to have really good braking. Your
vehicle was designed and tested with top
-quality GM
brake parts. When you replace parts of your braking
system
-- for example, when your brake linings wear
down and you have to have new ones put in
-- be sure
you get new approved GM replacement parts. If you
don't, your brakes may no longer work properly. For
example, if someone puts in brake linings that are wrong
for your vehicle, the balance between your front and
rear brakes can change
-- for the worse. The braking
performance you've come to expect can change in many
other ways if someone puts in the wrong replacement
brake parts.
Battery
Your new vehicle comes with an ACDelco Freedom

battery. When it's time for a new battery, we
recommend an ACDelco Freedom battery. Get one
that has the replacement number shown on the
original battery's label.
Vehicle Storage
If you're not going to drive your vehicle for 25 days
or more, remove the black, negative (
-) cable from
the battery. This will help keep your battery from
running down.
CAUTION:
Batteries have acid that can burn you and gas
that can explode. You can be badly hurt if you
aren't careful. See ªJump Startingº in the Index
for tips on working around a battery without
getting hurt.
Contact your dealer to learn how to prepare your vehicle
for longer storage periods.
Also, for your audio system, see ªTheft
-Deterrent
Featureº in the Index.

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6-54
CAUTION:
Rust or dirt on a wheel, or on the parts to which
it is fastened, can make wheel nuts become loose
after a time. The wheel could come off and cause
an accident. When you change a wheel, remove
any rust or dirt from places where the wheel
attaches to the vehicle. In an emergency, you can
use a cloth or a paper towel to do this; but be
sure to use a scraper or wire brush later, if
you need to, to get all the rust or dirt off.
(See ªChanging a Flat Tireº in the Index.)
When It's Time for New Tires
One way to tell when it's
time for new tires is to
check the treadwear
indicators, which will
appear when your tires have
only 1/16 inch (1.6 mm) or
less of tread remaining.
Some commercial truck
tires may not have
treadwear indicators.
You need a new tire if any of the following statements
are true:

You can see the indicators at three or more places
around the tire.

You can see cord or fabric showing through the
tire's rubber.

The tread or sidewall is cracked, cut or snagged deep
enough to show cord or fabric.

The tire has a bump, bulge or split.

The tire has a puncture, cut or other damage that
can't be repaired well because of the size or location
of the damage.

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6-78
Air Conditioning Refrigerants
Not all air conditioning refrigerants are the same. If the air conditioning system in your vehicle needs refrigerant, be
sure the proper refrigerant is used. If you're not sure, ask your dealer.
See the refrigerant charge label under the hood for information regarding refrigerant capacity.
Normal Maintenance Replacement Parts
Replacement part numbers listed in this section are based on the latest information available at the time of printing,
and are subject to change. If a part listed in this manual is not the same as the part used in your vehicle when it was
built, or if you have any questions, please contact your GM truck dealer.
These specifications are for information only. If you have any questions, see the service manual for the chassis or
refer to the body manufacturer's publications.
VIN Code M R J
Oil Filter* PF1218
PF1218
PF1218
Air Cleaner Filter* A1300C

A1300C

A1300C


PCV Valve* CV769C CV769C CV774C
Spark Plugs* 41
-932 41-932 41-932
Fuel Filter* GF626 GF626 GF626
Wiper Blades** 22154886 22154886 22154886
Wiper Blade Type Trico Trico Trico
Wiper Blade Length 18 inches (45.0 cm) 18 inches (45.0 cm) 18 inches (45.0 cm)
*AC part number
**GM part number
Use a PF52 oil filter if your vehicle has
four
-wheel drive.


A1301C high
-capacity air cleaner filter.

Short Trip/City Scheduled Maintenance -- Gasoline Engines
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7-9
** Drive axle service (see ªRecommended Fluids and
Lubricantsº in the Index for proper lubricant to use):

Check fluid level and add fluid as needed. If driving
in dusty areas or when towing a trailer, drain fluid
and refill every 15,000 miles (25 000 km).

If your vehicle has a locking differential, drain fluid
and refill at first engine oil change.
More frequent lubrication may be required for
heavy
-duty or off-road use.

3500 HD Models with applications requiring
extreme overload/trailer towing conditions and
high
-speed (above 45 mph or 70 km/h) conditions
for extended periods of time must have the drive axle
fluid changed every 30,000 miles (50 000 km).
See ªRecommended Fluids and Lubricantsº in
this section.

Long Trip/Highway Scheduled Maintenance -- Gasoline Engines
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7-30
The services shown in this schedule up to 100,000 miles
(166 000 km) should be performed after 100,000 miles
(166 000 km) at the same intervals. The services shown
at 150,000 miles (240 000 km) should be performed at
the same interval after 150,000 miles (240 000 km).
See ªOwner Checks and Servicesº and ªPeriodic
Maintenance Inspectionsº following.
Footnotes
 The U.S. Environmental Protection Agency or the
California Air Resources Board has determined that the
failure to perform this maintenance item will not nullify
the emission warranty or limit recall liability prior to the
completion of the vehicle's useful life. We, however,
urge that all recommended maintenance services be
performed at the indicated intervals and the maintenance
be recorded.
# Lubricate the front suspension, kingpin bushings,
steering linkage, transmission shift linkage, transfer case
shift linkage, parking brake cable guides, rear drivelinecenter splines, front axle propshaft spline and brake
pedal springs. Ball joints and kingpin bushings should
not be lubricated unless their temperature is 10F
(
-12C) or higher, or they could be damaged.
+ A good time to check your brakes is during tire
rotation. See ªBrake System Inspectionº under ªPeriodic
Maintenance Inspectionsº in Part C of this schedule.
** Drive axle service (see ªRecommended Fluids and
Lubricantsº in the Index for proper lubricant to use):

Check fluid level and add fluid as needed.

If your vehicle has a locking differential, drain fluid
and refill at first engine oil change.

3500 HD Models with applications requiring
high
-speed (above 45 mph or 70 km/h) operation for
extended periods of time must have the drive axle
fluid changed every 30,000 miles (50 000 km).