1996 GMC SIERRA service

What to Do with Used Oil
Did you know that used engine oil contains certain
elements that
may be unhealthy for your skin and could
even cause cancer? Don’t let used
oil stay on your skin
for very long. Clean your skin and nails with soap and
water, or
a good hand cleaner. Wash or properly throw
away clothing or rags containing used engine oil. (See
the manufacturer’s warnings about the use and disposal
of oil products.)
Used
oil can be a real threat to the environment. If you
change your own
oil, be sure to drain all free-flowing oil
from the filter before disposal. Don’t ever dispose
of oil
by putting it in the trash, pouring it on the ground, into
sewers,
or into streams or bodies of water. Instead,
recycle
it by taking it to a place that collects used oil. If
you have a problem properly disposing of your used oil,
ask your dealer, a service station or a local recycling
center for
help.
Air Cleaner
Your air cleaner is located between the battery and
coolant recovery tank.
ProCarManuals.com

The air cleaner assembly
has an indicator that lets
you know when the air filter
is dirty and needs to be
serviced.
The indicator is
located
in the air intake tube
between the air cleaner and
the engine.
See “Owner Checks and Services”
in the Index on when
to check the indicator.
If the area inside the clear section of the indicator is
green, no air filter service is required. When the area
inside the indicator is orange and
CHANGE AIR
FILTER appears, the filter should be replaced.
To remove the air filter, unhook the retaining clips and
remove the cover. Lift the filter and the connected duct
out of the air cleaner housing. Hold the duct and remove
the filter by both pulling and twisting the
filter away
fram the duct. Care should be taken
to dislodge as little
dirt as possible.
Clean the filter sealing surface of the duct and the
filter housing.
6-17
ProCarManuals.com

Install the new filter by pushing it all the way to the stop
on the duct.
Install
the duct and the filter into the air cleaner housing.
Make sure that the duct fits properly into the housing.
Install
the cover and fasten the two retaining clips.
After the air filter
is properly serviced, the indicator
should
be reset. Push the button on top of the indicator
to reset it to the green (clean) filter zone. Refer
to the
Maintenance Schedule to determine when to
replace the air filter.
See “Scheduled Maintenance Services”
in the Index.
I
Operating the engine with the air cleaner off can
cause you
or others to be burned. The air cleaner
not only cleans the air, it stops flame
if the engine
backfires.
If it isn’t there, and the engine
backfires,
you could be burned. Don’t drive with
it
off, and be careful working on the engine with
the
air cleaner off.
I NOTICE:
If the air cleaner is off, a backfire can cause a
damaging engine fire. And, dirt can easily get
into your engine, which
will damage it. Always
have the air cleaner
in place when you’re driving.
6-18
ProCarManuals.com

Automatic Transmission Fluid
When to Check a1 C’ -ge
A good time to check your auromarlc 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
90°F (32°C) or higher.
0 In hilly or mountainous terrain.
0 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, the
fluid and filter
do not require changing.
See “Scheduled Maintenance Services’’
in the Index.
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 on the dipstick.
NOTICE:
Too much or too little fluid can damage your
transmission.
Too much can mean that some of
i 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 90°F (32°C).
0 At high speed for quite a while.
In heavy traffic -- especially in hot weather.
While pulling a trailer.
To get the right reading, the fluid should be at normal
operating temperature, which
is 180°F to 200°F (82°C
to 93°C).
6-19
ProCarManuals.com

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.
II
Check the fluid level only when your engine is off, the
vehicle
is parked on a level place and the transmission
is cool enough for you to rest your fingers on the
transmission case.
Then, follow these steps:
1. Remove the filler plug.
2. Check that the lubricant level is up to the bottom of
the filler plug hole.
3. If the fluid level is good, install the plug and be sure
it is fully seated. If the fluid level is low, add more
fluid as described in the next steps.
6-22
ProCarManuals.com

How to Add Fluid
Here’s how to add fluid. Refer to the Maintenance
Schedule
to determine what kind of fluid to use. See
“Recommended Fluids and Lubricants” in the Index.
1. Remove the filler plug.
2. Add fluid at the filler plug hole. Add only enough
fluid to bring the fluid 1evel.u~ to tbe bottom
of the
filler plug hole.
3. Install the filler plug. Be sure the plug is fully seated.
Hydraulic Clutch
The hydraulic clutch system in your vehicle is
self-adjusting. A slight amount of play
(1/4 inch to
1/2 inch or 6 mm to 12 mm) in the pedal is normal.
It isn’t a good idea
to “top off’ your clutch fluid.
Adding fluid won’t correct a leak. A fluid loss in this
system could indicate a problem. Have the system
inspected and repaired.
When to Check and, What to Use
Refer to the Maintenance
Schedule, Owner Checks
and Services, to determine
how often you should
check the fluid level.in
your clutch master cylinder
reservoir and for the proper
fluid. See “Owner
Checks and Services” and
“Recommended Fluids and
Lubricants’’ in the Index.
How to Check
The proper fluid should be added if the level does not
reach the bottom
of the diaphragm when it’s in place in
the reservoir. See the instructions
on the reservoir cap.
6-23
ProCarManuals.com

Rear Axle
When to Chc d Change Lubricant
Refer to the Maintenance Schedule to determine how
often to check the lubricant and when to change
it. See
“Scheduled Maintenance Services”
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.
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:
0 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
(SO 000 km). Fluid capacity is 4.12 quarts (3.9 L).
What to Use
Refer to the Maintenance Schedule to determine what
kind
of lubricant to use. See “Recommended Fluids and
Lubricants”
in the Index.
6-24
ProCarManuals.com

Front Axle
When to Check and Change Lubricant
Refer to the Maintenance Schedule to determine how
often
to check the lubricant and when to change it. See
"Scheduled Maintenance Services"
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.
If the differential is at operating temperature (warm),
add enough lubricant
to raise the level to the bottom of
the filler plug hole.
If the differential is cold, add enough lubricant to raise
the level
to 1/2 inch (1 2 mm) below the filler plug hole.
What to Use
Refer to the Maintenance Schedule to determine what
kind
of lubricant to use. See "Recommended Fluids and
Lubricants"
in the Index.
Engine Coolant
The cooling system in your vehicle is filled with new
DEX-COOL
TM (orange-colored, silicate-free) engine
coolant. This coolant is designed
to remain in your
vehicle for
5 years or 100,000 miles (1 66 000 km),
whichever occurs first.
The following explains
your cooling system and how
to add coolant when it is low. If you have a problem
with engine overheating, see "Engine Overheating"
in
the Index.
6-26
ProCarManuals.com