
A CAUTION: 
It can  be dangerous to  get out  of your  vehicle  if the  shift  lever is 
not  fully  in “P” (Park)  with the parking  brake  firmly  set. Your 
vehicle  can  roll. 
If’ you  have  left  the engine  running, the  vehicle  can  move 
suddenly.  You or  others  could  be injured. 
To be sure  your  vehicle 
won’t  move,  even  when  you’re  on  fairly level ground,  use the 
steps  that follow. 
If you  have  four-wheel  drive and your  transfer  case  is  in “N” 
(Neutral),  your  vehicle  will  be  free to roll,  even if your shift  lever 
is  in 
“P” (Park). So, be  sure  the  transfer  case is in a drive  gear 
- not  in “N” (Neutral). 
If you are parking  on a hill, or if  you’re  pulling  a  trailer,  also  see 
“Parking 
On Hills”  in  the  Index. 
When You Are  Ready  to Leave  After  Parking on a Hill 
1.  Apply your regular brakes and hold the pedal down while you: 
Start  your engine; 
Shift  into a gear;  and 
0 Release the parking brake. 
2. Let up on the brake pedal. 
3. Drive  slowly until the trailer is  clear of the  chocks. 
4. Stop  and have  someone pick up and store the chocks. 
Maintenance  When  Trailer  Towing 
Your  vehicle  will need service more often  when you’re pulling a trailer.  See 
the  Maintenance  Schedule  for  more on this. Things that are especially 
important  in trailer operation  are automatic 
fluid (don’t overfill),  engine oil, 
axle  lubricant, belts,  cooling system, and brake adjustment. Each  of these 
is 
covered in this manual,  and the Index  will help  you find them quickly.  If 
you’re trailering, it’s 
a good idea  to review  these sections before  you start 
your trip. 
Check periodically  to  see that all  hitch nuts and bolts  are tight. 
Trailer  Light  Wiring 
See  “Trailer Wiring  Harness” in the Index. 
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Brakes 
Brake Master Cylinder 
Your brake master 
cylinder  is here. It  is 
filled  with 
DOT-3 
brake fluid. 
There  are only  two reasons 
why the brake fluid  level in your master  cylinder 
might 
go down, The first is that the brake fluid goes down  to an acceptable 
level  during  normal brake lining wear.  When  new linings are put  in, the 
fluid  level goes  back up. The  other  reason is  that fluid is leaking 
out of the 
brake  system. 
If it is,  you  should have your  brake system  fixed, since a leak 
means  that sooner  or  later your brakes 
won’t work well, or won’t work  at 
all. 
So, it isn’t  a good  idea to “top off’ your brake fluid. Adding  brake  fluid 
won’t  correct  a  leak. 
If you add fluid  when your linings  are worn, then 
you’ll  have 
too much  fluid when you get new  brake linings.  You should  add 
(or  remove)  brake fluid, 
as necessary, only  when work is done on the brake 
hydraulic  system. 
Refer 
to the Maintenance  Schedule  to  determine  when to check your brake 
fluid.  See “Periodic Maintenance  Inspections” 
in the Index. 
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Brake  Wear 
Your vehicle has front disc brakes and rear  drum brakes. If you have  a 
C 3500 HD model,  it has  four-wheel  disc brakes. 
Disc brake  pads have  built-in wear indicators that make 
a high-pitched 
warning  sound  when the brake pads are  worn and new  pads  are needed.  The 
sound  may come  and go  or  be heard 
all the time your vehicle is moving 
(except  when  you  are pushing on the brake  pedal firmly). 
The  brake  wear  warning  sound  means  that  sooner or later  your 
brakes  won’t  work  well.  That  could  lead  to  an  accident. 
When 
you hear  the  brake  wear  warning  sound,  have your vehicle 
serviced. 
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. 
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. 
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  brakes 
replaced, have the rear brakes inspected, too. 
Brake  linings  should always  be replaced 
as complete  axle sets. 
Brake 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. 
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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. 
Replacing  Brake  System  Parts 
The braking  system  on a modern  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.  Vehicles  we  design  and test have  top-quality 
GM brake parts in 
them, as your vehicle  does when it is  new.  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  genuine 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. 
Other  Maintenance  Hems 
Front  Suspension  and  Steering  Linkage 
Your maintenance  schedule will tell you  how  often to lubricate  the fittings. 
See  “Recommended  Fluids  and Lubricants” 
in the Index  for the proper 
lubricant to use. 
Front  Wheel  Bearings 
Your  vehicle has  front wheel bearings  that must  be cleaned  and repacked. 
Your  maintenance  schedule 
will tell you how often this must be  done. 
Front  Shock  Absorbers 
The  front  shock  absorbers  of your vehicle do  many  things.  They  help the 
vehicle ride  smoothly and also control 
the travel of the  suspension  system. 
When the  shock  absorbers  are  serviced,  any replacement  shock absorbers 
must  be 
the same as the original  equipment  shock absorbers in both 
extended  length and strength. 
NOTICE: 
If you  use  shock  absorbers  that  are  not  the  same  as the  original 
shock  absorbers,  the  shock  absorbers 
or suspension  system 
could  be  damaged. 
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After you’ve  loaded your vehicle and camper,  drive to a weigh station  and 
weigh 
on 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 CertificatiodTire  label to find  out 
your  CWAR  and GVWR. 
If 
you’ve gone  over  your weight ratings, move  or take  out  some  things until 
all the weights fall 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 “Consumer  Information,  Truck-Camper 
Loading.” 
Trailer  Recommendations 
You  must subtract your  hitch loads from  the CWR  for  your vehicle. Weigh 
your  vehicle  with 
the trailer hitch attached, so that you won’t go over the 
GVWR  or  the GAWR. 
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  “Trailer Towing’’ 
in the Index. 
Pickup  Conversion To Chassis Cab 
General  Motors  is aware  that some  vehicle  owners  may consider  having the 
pickup box removed and 
a commercial  or recreational  body installed. 
Before 
you do so, first  contact the GM Zone Office for your area  for 
information on such  conversions.  (See the “Warranty  and  Owner 
Assistance”  booklet  for  Zone  Office.)  Owners  should be aware that,  as 
manufactured,  there are differences between  a  chassis  cab and a pickup  with 
the  box  removed  which  may  affect vehicle safety.  The  components 
necessary  to  adapt 
the pickup to permit  its safe  use  with a specialized  body 
should  be installed  by a body  builder 
in accordance with the information 
available  from 
the Zone Office. 
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24. DRIVE AXLE SERVICE? - Check readfront  axle  fluid level and 
add 
as needed. Check constant velocity  joints and axle  seals for 
leaking. 
0 
0 
0 
0 
Locking  differential - Drain fluid at first  oil change  and refill. 
Check fluid level and add 
as needed at subsequent oil  changes. In 
dusty areas,  or trailer towing applications drain fluid at every 
15,000 miles  (24 135 kilometers) and refill. 
Standard  differential - Check  fluid level and add as needed at 
every 
oil change.  In dusty areas,  or trailer towing applications, 
drain  fluid every 
15,000 miles  (24 I35 kilometers)  and refill. 
More  frequent  lubrication  may  be required  on  heavy-duty  or 
off-road  use. 
3500 HD Models - 3500 HD Models with applications requiring 
extreme  overload/trdiler  tow conditions 
and high  speed  conditions 
(above  45  mph (72 
kdh)) for extended periods of time must 
change  drive  axle  fluid every 
3,000 miles (4828 kilometers) or 3 
months, whichever  comes first, OR must use  75W-140  synthetic 
fluid  meeting 
GM specifications.  See “Recommended Fluids and 
Lubricants”  at the  end  of this section  for the proper fluid to use. 
25. 
BRAKE SYSTEM  INSPECTION-f - When the engine  oil is 
changed,  inspect the lines and hoses  for proper hookup, binding, leaks, 
cracks,  chafing,  etc.  Check the parking brake adjust, and the fluid level 
in the master cylinder. A low  fluid level can  indicate worn disc brake 
pads  which  may  need 
to be  serviced. 
When the wheels are removed  for rotation, inspect  disc brake  pads  for 
wear and rotors  for  surfxe condition. Also inspect drum brake  linings 
for  wear and cracks. Inspect  other brake parts, including  drums, wheel 
cylinders,  parking brake, etc., at the  same  time. Remove any 
rust or dirt 
from  the  wheel and mounting surfaces before mounting the wheel. 
Inspect  brakes  more  often  if  driving  habits or conditions  result  in 
frequent  braking. 
?A fluid loss  in these systems  may indicate a problem. Have them 
inspected and repaired  at  once. 
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Owner Checks and  Services 
Listed below are  owner  checks  and services which should  be made  at the 
time period  specified  to  help ensure  proper  safety, emission performance, 
and  dependability 
of your vehicle. 
Be  sure  any necessary  repairs  are  completed  at once. Whenever  any  fluids 
or  lubricants  are added  to your vehicle,  make  sure they are 
the proper  ones, 
as shown 
in this  Section. 
At  Least  Once a Month 
Tire  inflation  pressure  check - Check the tires for  proper  inflation. If 
they are low, inflate them to the level  specified on the  Certification/Tire 
label.  See  “Loading  Your  Vehicle”  or “Inflation-Tire  Pressure” 
in the  Index. 
At  Least  Once  a  Year 
Key  lock  cylinder  lubrication - Lubricate  key lock  cylinders  with engine 
oil.  See 
the “Recommended  Fluid and Lubricants”  chart in this section. 
Transmission  neutral  or clutch  start  switch  operation - 
1. Before  you start,  be  sure  you have  enough  room around the vehicle. 
2. Firmly apply both  the manual parking  brake and the  regular  brake. See 
“Brakes”  and “Parking  Brake” 
in the Index. Do not use the  accelerator 
pedal. 
3. Be ready  to turn off the  engine  immediately  if it starts. 
4. On  automatic  transmission  vehicles,  try to start the  engine in each gear. 
The  starter  should work only 
in “P’ (Park)  or “N” (Neutral). 
On  manual  transmission  vehicles,  put the shift  lever 
in “N” (Neutral), push 
the clutch down halfway, and try to start the engine. The  starter  should work 
only when the  clutch 
is pushed down  all  the way  to the floor. 
Steering  column  lock  operation - While  parked,  try to turn the key  to 
LOCK in each gear  shift position. 
With  an automatic  transmission,  the key should 
turn to LOCK only when 
the  gear  shift 
is in “P” (Park). 
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Index 
A 
Aircleaner ..................................................... 6-29 
Air  Conditioning 
............................................ 3.5. 6.S0 
Aircontrols 
.................................................. 3-7 
Low  Refrigerant Change  Detection 
................................ 3-8 
Refrigerant Capacity 
...................................... 3.97,  6.94 
SystemControls 
............................................... 3-6 
Antenna,  FixedMast 
............................................. 3-18 
Anti-Lock  Brakes (See “Brakes”) 
Appearancecare 
................................................ 6-80 
Materials Chart ............................................... 6-87 
Arbitration  Program 
............................................... 8-3 
Audiosystems 
................................................... 3-9 
AMRadio ................................................... 3-10 
AM-FM  Stereo Audio System  with Cassette  Deck ................... 3-12 
AM-FM  Stereo Audio System with Cassette  Deck  and Equalizer ........ 3-16 
Cassette  Deck 
................................................ 3-14 
Cassette  Tape Player Care 
....................................... 3-30 
Automatic  Transmission 
.......................................... 2-21 
Fluid 
....................................................... 6-30 
Axle  Front 
....................................................... 6-37 
Front  Locking  Feature 
.......................................... 2-36 
Rear 
........................................................ 6-39 
RearLocking 
.................................................. 6-39 
Battery 
........................................................ 6-52 
Belts  (See “Safety  Belts”) 
Better  Business  Bureau  Mediation 
.................................... 8-3 
Blizzard ....................................................... 4-35 
Brakes 
Anti-Lock 
.................................................... 4-6 
Fluid 
....................................................... 6-47 
Leakcheck 
.................................................. 6-47 
Master Cylinder 
.............................................. 6-46 
Parking 
..................................................... 2-28 
PedalTravel ................................................. 6-48 
Replacing Parts 
............................................... 6-49 
System  Warning  Light 
......................................... 2-70 
Trailer 
...................................................... 441 
In Emergencies ................................................ 4-7 
Break-In,  New  Vehicle 
........................................... 2- IO 
Bulb  Replacement ............................................... 6-97 
Replacement Chart 
............................................ 6-97 
Braking 
......................................................... 4-5 
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