1999 GMC C-SERIES engine oil

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6-39
ITEM NO. ITEM REMARKS
1 Brake Camshaft
, Brake Caliper
Rails (If Equipped)$One fitting each (apply sparingly). For caliper rails,
apply Aero Shell #5 Lubricant.
2 Steering Column Slip Joint* One fitting.
3 Steering Drag Link Ends One fitting at each end.
4 Steering Column U
-Joints One fitting each joint.
5 Pivot Points and Hinges Apply chassis lubricant.
6 Slack Adjuster
One fitting.
7 Brake Cam Roller Pins at interface
of pin and shoe
Apply engine oil.
8 Front Steering Knuckles One fitting each side, lower bushing (hand
-operated
grease gun only). Hand
-pack upper bearing.
9 Front Wheel Bearings Hand
-pack or lubricate.
10 Steering Tie Rod Ends One fitting each end.
11 Spring Slip Pads*
(Multi
-Leaf Only)Apply chassis lubricant.
12 Clutch Release Bearing* Cup or fitting.
13 Battery Terminal
(except ªSTº type)Keep coated with petroleum jelly.
14 Parking Brake Bell Crank*$ One fitting.
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6-41
Tandem Axle ModelsITEM
NO.ITEM REMARKS
1 Brake Camshafts One fitting each.
2 Propshaft U
-Joint One fitting each joint
(1480 and 1550 Series).
Lubricate with GM Part
No. 1051344, Wheel
Bearing Lubricant.
4 Brake Shoe
Roller PinsApply engine oil at pin
to shoe joint only.
5 Rear Spring Pin One fitting each side.
6 Wheel Bearings Hand
-pack or lubricate.
7 Rear Axles Fill to level of filler plug.
8 Propshaft Slip
JointTwo fittings each side.
Lubricate with GM Part
No. 1051344 Wheel
Bearing Lubricant.
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6-44
Other Service Items
Component Box
Your vehicle has a component box along the left frame rail.
What is in the box depends on what options are on your
vehicle. Normally, the fuel filter, air dryer, Luberfiner oil
filter, emission canister or other components are in there.
To get into the box, you first have to remove the top
cover. To do that, remove the two 8 mm bolts on top and
the single 8 mm bolt at the top front. Then, pull the
cover toward you and lift it off.You can then remove the front cover if you need to, by
removing the two 8 mm bolts and pulling it off.
When you're through, be sure to put the front cover on,
before you put on the top cover.
Fuel Filter (Gasoline Engines)
The steel fuel filter is located inside the component box
at the rear. See your Maintenance Schedule for
recommended service intervals.
If your vehicle is equipped with the optional Davco
spin
-on type filter, it is also located in the component box.
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6-45 Fuel Filter (Diesel Engines)
The ACDelco
fuel filter is located in the component
box. See your Maintenance Schedule for recommended
service intervals.
Primary Fuel Filter and Water Separator
(Option)
If you have a Caterpillar

diesel engine, you may
have this spin
-on filter.
It is in the component box
on the driver's side behind
the fender.
It has a clear plastic drain bowl at the bottom. Check the
drain bowl occasionally for any water or particles. To
drain the bowl, shut off the engine. Then partially open
the drain valve at the bottom of the filter. See ªEngine
Oilº in the Index for proper disposal procedures.
Secondary Fuel Filter and Water
Separator/Heater (Option)
If you have a Caterpillar

diesel engine, you may have
this spin
-on filter and fuel
separator/heater. It is
mounted on the passenger's
side of the engine.
It has a metal drain bowl at the bottom. Occasionally, check
the bowl for any water or particles. To check or drain the
bowl, shut off the engine. Then push up on the spring loaded
drain valve until clear fuel is flowing from the valve. The
particles or water will drain out first. See ªEngine Oilº in the
Index for proper disposal procedures.
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6-46 Automatic Ether Injection System (Option)
If your diesel engine vehicle
has this feature, the ether
cylinder is on the upper
right rear side of the engine
compartment.
To change an empty ether cylinder, follow these steps.
1. Loosen the 5/16 inch screw head on the
cylinder
-to-bracket clamp.
2. Spread the clamp apart.3. Clean any dirt from the neck of the cylinder and the
top of the valve before you take out the cylinder.
4. Check the inside of the valve for any foreign matter.
Clean the valve as necessary.
5. Cover the valve to protect it from dirt and take out
the cylinder.
6. Install a new gasket whenever you take out the
cylinder. Use only one gasket and spread a light film
of clean oil on it before installation.
7. Put in the new cylinder. Turn it clockwise until it just
starts to contact the gasket.
8. Tighten the cylinder another half turn (180 degrees).
Don't over
-tighten.
9. Retighten the cylinder clamp.
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6-71
Name Circuits Protected
CHAS Exhaust Brake, Air Suspension
Dump Valve, Air Dryer, HYD
ABS ECHU
PARK LP Auxiliary Wiring, Air Conditioner
Controls, Parking Lamps, Turn
Signals, Taillamps, Stoplamps,
Marker Lamps, Trailer Running
Lamps, Lighted Mirrors, Radio
Receiver, Mirror Clearance Lamps
HORN Horn/Diagnostic Connector
PRK BRK Parking Brake Module
FUEL Heated Fuel Filter (Diesel
Engines) or Fuel Pump
(Gasoline Engines)
AXLE Heated Mirrors, Radiator Shutters,
Tw o
-Speed Axle Motor,
Tw o
-Speed Axle Switch
MRKR LP Roof Marker Lamps,
Trailer Marker Lamps,
Marker Lamp RelayName Circuits Protected
CIG/AUX Cigarette Lighter,
Auxiliary Power Jacks
AUX Auxiliary Wiring Relay
IGN RLY/VIN Vehicle Interface Module
(Diesel Engines) or Generator,
Coil, Injectors (Gasoline Engines)
WDO Power Windows
CRNK Starter Relay
IGN SW Instrument Panel Cluster Telltales
AUX Auxiliary Wiring
RDO Radio, Auxiliary Wiring
DR LK Power Door Locks
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6-74
Replacement Bulbs
It is recommended that you use an AC
type bulb
whenever you need to replace one.
Before you replace any bulbs, be sure that all lamps are
off and the engine isn't running.
Capacities and Specifications
Replacement part numbers listed in this section are
based on the latest information available at the time of
printing. They are subject to later change. If a part listed
here isn't the same as the part in your vehicle when it
was built, or if you have any questions, please contact
your GM Truck dealer.
Engine Identification and Data
Engine RPO LG5 LP4/L21
Engine Type 7.2L L6 7.4L V8
Fuel System HEUI SPFI
Firing Order
1
-5-3-6-2-41-8-4-3-6-5-7-2
Wheel Nut Torque
Refer to ªTightening the Wheel Nutsº in this section for
wheel nut torque information.
Cooling System Capacity
Model Quarts (Liters)
7.2L 32.0 (30.0). . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
with automatic transmission 30.0 (28.4). . . . . . . . . .
7.4L 25.0 (23.7). . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
with automatic transmission 23.0 (22.7). . . . . . . . . .
Above capacities (volumes) are approximate.
Crankcase Capacity
Capacities (volumes) shown are for normal refill. Add
oil as indicated when the oil filter element is changed.
Capacities given are approximate
-- keep level within
the operating range. Do not operate with fluid level
below the ADD line.
Engine
Capacity
-- Quarts (Liters)
7.2L 21 (19.0)*
7.4L 8 (7.5)
*Additional oil is required with auxiliary oil filter
systems. Make sure to add enough extra oil to fill the
auxiliary oil filter system. For vehicles equipped with
the LUBERFINER 750
-C, add 14 quarts (13.25 L).
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6-75
Extending the recommended oil change interval requires
the use of an infrared oil analysis program which shows
the condition of the oil and its additives. For more
information, consult your GM Truck dealer, who is an
authorized Caterpillar

engine dealer.
Transmission Capacity
Capacities (volumes) shown are approximate. For
manual transmissions, the correct oil level is to the
bottom of the fluid fill plug opening. The oil capacity
will vary, due to the angle of the transmission, with the
vehicle. For automatic transmissions, see the Allison
Automatic Transmission Operator's Manual for oil
check and maintenance information.
Manual Transmission Pints (Liters)
RT6609 12.0 (5.7). . . . . . . . . . . . . . . . . . . . . . . . . . . . .
RT6610 12.0 (5.8). . . . . . . . . . . . . . . . . . . . . . . . . . . . .
RTO6610 12.0 (5.8). . . . . . . . . . . . . . . . . . . . . . . . . . . RT6613 16.0 (7.5). . . . . . . . . . . . . . . . . . . . . . . . . . . . .
RT7608LL 19.5 (9.3). . . . . . . . . . . . . . . . . . . . . . . . . .
RT8609 15.0 (7.0). . . . . . . . . . . . . . . . . . . . . . . . . . . . .
FS4205A, FS4205B, FS4205C 12.5 (5.9). . . . . . . . . .
5205A, FS5205C 12.5 (5.9). . . . . . . . . . . . . . . . . . . . .
FS5306 18.0 (8.5). . . . . . . . . . . . . . . . . . . . . . . . . . . . .
FS6305A, FS6305B 19.0 (9.0). . . . . . . . . . . . . . . . . . .
FS6306 19.5 (9.2). . . . . . . . . . . . . . . . . . . . . . . . . . . . .
FS7206 20.0 (9.5). . . . . . . . . . . . . . . . . . . . . . . . . . . . .
T8607B 36.0 (17.0). . . . . . . . . . . . . . . . . . . . . . . . . . .
Automatic Transmission Pints (Liters)
AT542 (for oil pan filter change) 30.0 (14.0)*. . . . . . .
AT545 (for oil pan filter change) 40.0 (19.0)*. . . . . . .
MT643 (for oil pan filter change) 13.0 (24.5)*. . . . . .
MT653 (for oil pan filter change) 36.0 (17.0)*. . . . . .
*Add two pints (one liter) when changing spin
-on filter.
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