Chevrolet T-Series Owner's Manual page 274

45,000 Miles (72 000 km)
Inspect engine air cleaner filter change
indicator. If necessary, replace the filter.
If vehicle is driven in dusty/dirty conditions,
inspect filter change indicator at every engine
oil change. See Engine Air Cleaner/Filter
on page 192 for more information.
Check fluid levels (or every 3 months,
whichever occurs first). (1) (5)
Replace fuel filter (or every 750 hours of
engine operation, whichever occurs first).
Chassis lubrication service (or every 6 months,
whichever occurs first). (10)
Cooling system service. Clean the cooling
system filler cap with clean water, clean
the core, pressure test the cap and the system
for proper pressure capability, and inspect
the condition of cooling and heater hoses and
clamps. Replace hoses if cracked, swollen,
or damaged.
Inspect door hinge pins and bushings and
replace as necessary.
Steering system service. (11)
Front and rear suspension service. (12)
274
Spring-to-axle U-bolts and shackle bolts
service. (14)
Exhaust system service (or every 6 months,
whichever occurs first). (2) (3) (15)
Wheels and tires service. (13)
Hydraulic brake service (or every 6 months,
whichever occurs first). (6) (30)
Parking brake service (or every 6 months,
whichever occurs first). (7)
Air brake service (or every 6 months, whichever
occurs first). (26)
Air brake automatic slack adjuster service (or
every 500 hours, whichever occurs first). (27)
Check air brake relay valve operation and check
for leaks (or every month, or every 300 hours,
whichever occurs first).
Clean air brake application valve (or every
3 months, or every 300 hours, whichever occurs
first). Lubricate linkage.
Air brake chamber service (or every 2 months,
whichever occurs first). (28)
Air brake system valve service (or every
3 months, or every 900 hours, whichever
occurs first). (31)