GMC T-Series 1999, Owner'S Manual, Page: 287 / 344

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Scheduled Maintenance (Except DURAMAX
t
DIESEL)
7-25
(23) = Wheel bearing service:
D Grease type
--
Clean, inspect and lubricate with the
proper wheel bearing grease at designated intervals
or when hubs are removed. See “Recommended
Fluids and Lubricants” in the Index.
D Oil
-
filled type
--
Some wheel bearings are lubricated
by rear axle lubricant. When you have oil
-
filled
hubs, use lubricant identical to that used in your rear
axle. Lubricant change intervals are the same for
front and rear axles. However, you must maintain oil
level at the OIL LEVEL mark between change
intervals. See “Recommended Fluids and
Lubricants” in the Index.
(24) = Check the air intake system installation to see
that gaskets are seated properly and all hose
connections, fasteners and other components are tight.
For gasoline engines, also check to be sure the air
cleaner housing is properly seated, that the cover fits
tightly and that the wing nut is tight. Tighten
connections and fasteners or replace parts as required.
(25) = Check thermostatically controlled air
cleaner installation to make certain that all ducts are
connected and correctly installed. Also, check valve for
proper operation.
(26) = Evaporative Control System Service (if
equipped): Check all fuel and vapor lines and hoses
for proper connections and correct routing (or every
24 months, whichever occurs first). Replace parts
as needed.
(27) = Replace air cleaner filter (or every 24 months,
whichever occurs first). Replace filter more often if
driving in dusty conditions. Ask your dealer for the
proper replacement intervals for your driving conditions.
(28) = Replace spark plugs. Inspect wires for damage.
Check the wire boot and boot heat shield fit at spark
plugs and coil. Replace parts as needed.
(30) = Check the fuel tank, fuel cap and fuel lines for
damage which could cause leakage. Inspect fuel cap for
correct sealing ability and any indications of damage.
Check fuel cap gasket for even filler neck imprint.
Replace parts as needed.