1999 GMC ENVOY automatic transmission

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4-54 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 transmission fluid (don't
overfill), engine oil, axle lubricant, belt, cooling system
and brake system. 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 Wiring Harness
The heavy-duty trailer wiring is an eight-wire harness
assembly. The harness is stored under the vehicle, on the
driver's side corner frame rear crossmember. The
heavy
-duty trailer wiring has a 30-amp feed wire with
an in
-line fuse located by the junction block. See ªFuses
and Circuit Breakersº in the Index. The harness does not
have a connector and should be wired by a qualified
electrical technician. The technician can use the
following color code chart when connecting the wiring
harness to your trailer.

Dark Blue: Use for electric trailer brakes or
auxiliary wiring.
Red: Use for battery charging; it connects to the
starter solenoid.

Light Green: Back
-up lamps.

Brown: Taillamps and parking lamps.

Yellow: Left stoplamp and turn signal.

Dark Green: Right stoplamp and turn signal.

White (Heavy Gauge): Ground wire.

White (Light Gauge): Auxiliary stoplamp.
Securely attach the harness to the trailer, then tape or
strap it to your vehicle's frame rail. Be sure you leave it
loose enough so the wiring doesn't bend or break, but
not so loose that it drags on the ground. Store the
harness in its original place. Wrap the harness together
and tie it neatly so it won't be damaged.
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5-4
2. Get the vehicles close enough so the jumper cables
can reach, but be sure the vehicles aren't touching
each other. If they are, it could cause a ground
connection you don't want. You wouldn't be able to
start your vehicle, and the bad grounding could
damage the electrical systems.
To avoid the possibility of the vehicles rolling, set
the parking brake firmly on each vehicle. Put an
automatic transmission in PARK (P) or a manual
transmission in NEUTRAL (N) before setting the
parking brake.
3. Turn off the ignition on both vehicles. Unplug
unnecessary accessories plugged into the cigarette
lighter or the accessory power outlets. Turn off all
lamps that aren't needed as well as radios. This will
avoid sparks and help save both batteries. In
addition, it could save your radio!
NOTICE:
If you leave your radio on, it could be badly
damaged. The repair wouldn't be covered by
your warranty.
4. Open both hoods and locate the batteries. Find the
positive (+) and negative (
-) terminals on each battery.
CAUTION:
Using a match near a battery can cause battery
gas to explode. People have been hurt doing this,
and some have been blinded. Use a flashlight if
you need more light.
Be sure the battery has enough water. You don't
need to add water to the ACDelco Freedom

battery installed in every new GM vehicle. But if
a battery has filler caps, be sure the right amount
of fluid is there. If it is low, add water to take care
of that first. If you don't, explosive gas could
be present.
Battery fluid contains acid that can burn you.
Don't get it on you. If you accidentally get it in
your eyes or on your skin, flush the place with
water and get medical help immediately.
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6-
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6-1
Section 6 Service and Appearance Care
Here you will find information about the care of your vehicle. This section begins with service and fuel information,
and then it shows how to check important fluid and lubricant levels. There is also technical information about your
vehicle, and a part devoted to its appearance care.
6
-2 Service
6
-3 Fuel
6
-5 Fuels in Foreign Countries
6
-5 Filling Your Tank
6
-7 Filling a Portable Fuel Container
6
-8 Checking Things Under the Hood
6
-10 Engine Oil
6
-14 Engine Air Cleaner/Filter
6
-15 Automatic Transmission Fluid
6
-18 Rear Axle
6
-19 Four-Wheel Drive
6
-21 Radiator Pressure Cap
6
-21 Thermostat
6
-21 Engine Coolant
6
-24 Power Steering Fluid
6
-25 Windshield Washer Fluid
6
-26 Brakes6
-31 Battery
6
-31 Bulb Replacement
6
-35 Windshield Wiper Blade Replacement
6
-37 Tires
6
-45 Appearance Care
6
-46 Cleaning the Inside of Your Vehicle
6
-48 Care of Safety Belts
6
-50 Cleaning the Outside of Your Vehicle
6
-53 GM Vehicle Care/Appearance Materials
6
-54 Vehicle Identification Number (VIN)
6
-54 Service Parts Identification Label
6
-54 Electrical System
6
-60 Replacement Bulbs
6
-60 Capacities and Specifications
6
-61 Air Conditioning Refrigerants
6
-61 Normal Maintenance Replacement Parts
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6-15
CAUTION:
Operating the engine with the air cleaner/filter
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/filter off.
NOTICE:
If the air cleaner/filter 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/filter in place when
you're driving.
Automatic Transmission Fluid
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 15,000 miles
(25 000 km) 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 you do not use your vehicle under any of these
conditions, change the fluid and filter every
50,000 miles (83 000 km).
See ªScheduled Maintenance Servicesº in the Index.
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6-18 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.
Rear 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 ªScheduled Maintenance Servicesº 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.
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6-57
Fuse/Circuit
BreakerUsage
14 Power Locks Motor
15 4WD Switch, Engine Controls
(VCM, PCM, Transmission)
16 Air Bag
17 Front Wiper
18 Steering Wheel Audio Controls
19 Radio, Battery
20 Amplifier
21 HVAC I (Automatic),
HVAC Sensors (Automatic)
22 Anti
-Lock Brakes
23 Rear Wiper
24 Radio, Ignition
Engine Compartment Fuse Block
The fuse block is under the hood at the driver's side of
the engine compartment.
Remove the cover by turning the fastener
counterclockwise. To reinstall the fuse panel cover, push
in and turn the fastener clockwise.
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6-59
Name Usage
HORN Horn
BTSI Brake
-Transmission
Shift Interlock
B/U LP Back
-Up Lamps
DRL Daytime Running Lamps
(If Equipped)
IGN B Column Feed, IGN 2, 3, 4
RAP Retained Accessory Power
LD LEV Electronic Load Leveling
OXYSEN Oxygen Sensor
MIR/LKS Mirrors, Door Locks
FOG LP Fog Lamps
IGN E Engine
IGN A Starting and Charging, IGN 1
STUD #2 Accessory Feeds, Electric Brake
PARKLP Parking Lamps
LR PRK Left Rear Parking LampsName Usage
IGN C Starter Solenoid, Fuel Pump,
PRNDL
HTDSEAT Heated Seats
HVAC HVAC System
TRCHMSL Trailer Center High
-Mounted
Stop Light
HIBEAM High
-Beam Headlamps
RRDFOG Rear Defogger
TBC Truck Body Computer
CRANK Clutch Switch, NSBU Switch
HAZLP Hazard Lamps
VECHMSL Vehicle Center High
-Mounted
Stop Lamp
HTDMIR Heated Mirror
ATC Automatic Transfer Case
STOPLP Stoplamps
RR W/W Rear Window Wiper
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6-60
Replacement Bulbs
Lamps Quantity Number
Halogen Headlamps, Composite High Beam 2 9005 HB3
Tail and Stoplamps 4 3057
Front Sidemarker Lamps 2 194 NA
Front Turn Signal Lamps 2 3157
Turn Signal Lamps 2 3157 NA
Capacities and Specifications
Engine Description ªVORTECº 4300. . . . . . . . . . . .
Type V6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
VIN Code W. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Firing Order 1
-6-5-4-3-2 . . . . . . . . . . . . . . . . . . . . . .
Horsepower 190 at 4,400 rpm. . . . . . . . . . . . . . . . . . .
Thermostat Specification 195
F (91
C) . . . . . . . . . . .
Spark Plug Gap 0.060 inches (1.52 mm). . . . . . . . . .
Wheels and Tires
Wheel Nut Torque 100 lb-ft (140 N´m) . . . . . . . . . . .
Tire Pressure See the Certification/Tire label.. . . . . .
See ªLoading Your Vehicleº in the Index.
Capacities (Approximate)
Cooling System* 11.7 quarts (11.1 L). . . . . . . . . . . . .
Crankcase* 4.5 quarts (4.3 L). . . . . . . . . . . . . . . . . . .
Automatic Transmission
(Drain and Refill)* 5.0 quarts (4.7 L). . . . . . . . . . .
Differential Fluid
Front 2.6 pints (1.2 L). . . . . . . . . . . . . . . . . . . . . . .
Rear 4.0 pints (1.9 L). . . . . . . . . . . . . . . . . . . . . . . .
Fuel Tank 18.0 gallons (68.0 L). . . . . . . . . . . . . . . . . .
A/C Refrigerant 1.75 lbs. (0.79 kg) . . . . . . . . . . . . . .
of R
-134a
*After refill, the level must be checked.
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