GMC T-Series 1999 Owner's Manual page 312

Scheduled Maintenance (DURAMAX
(21) = Check shields and undercab insulation for
damage or looseness. Adjust or replace as needed.
(22) = Lubricate caliper housing, caliper support spring
and caliper support key.
(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
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.
Tighten connections and fasteners or replace parts
as required.
7-50
t
DIESEL)
(25) = Check injection timing; incorrect injection timing
could result in increased exhaust emission or smoke
emission or reduced engine output. With an injector
cleaning tool, clean the outside of the injector end.
(26) = Inspect all fuel line connections on the supply
pump, common rail and injector.
(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) = Adjust valve lash. Incorrect valve clearance will
-
filled
result in increased engine noise and reduced engine
output. Retorque rocker shaft bracket nuts before
checking and adjusting valve clearance. Intake and
exhaust valve clearance is 0.016 inch (0.4 mm),
cold adjustment.
(29) = Check curb idle speed at 6,500 miles
(10 400 km), 52,000 miles (83 200 km) and then
every 52,000 miles (83 200 km).
(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.
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