GMC TopKick 2007 Owner's Manual page 387

(13) = Check front and rear suspension. Look
for damaged, loose, or missing parts or parts
showing signs of wear or lack of lubrication.
Replace parts as needed.
(14) = Adjust tire pressures as indicated on the
Certification or Tire Information label for optimum
tire life. See Tires on page 320 for further
details. Check tires for excessive or abnormal
wear or damage. Also check for damaged wheels.
Replace wheels and/or tires as needed.
(15) = Check spring-to-axle U-bolts and shackle
bolts for proper torque. See the service manual for
torque sequence and specifications. When parts
are replaced, the torque must be checked and
adjusted more often during the first 6,000 miles
(10 000 km). Check torque at 500 miles (800 km)
and 2,000 miles (3 000 km) after first use of parts.
(16) = Check complete exhaust system and
cab areas near the exhaust system for broken,
damaged, missing, or out-of-position parts.
Also inspect for open seams, holes, loose
connections, or other conditions which could let
exhaust fumes seep into the driver compartment.
Needed repairs should be made at once. To
help maintain system integrity, replace exhaust
pipes whenever a new muffler is put on.
(17) = Check all gasoline engine drive belts for
cracks, fraying, and wear. Replace as needed.
(18) = Adjust valve lash. Incorrect valve clearance
will result in increased engine noise and reduced
engine output.
(19) = With the engine off and below normal
operating temperature, check to see that
the thermostatically controlled engine cooling
fan can be rotated by hand on viscous-operated
drives. Replace as needed.
(20) = Check shields and underhood insulation
for damage or looseness. Adjust or replace
as needed.
(21) = Inspect parking brake drum and linings for
wear or cracks and check linkage and adjustment.
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