Chevrolet T-Series Owner's Manual page 270

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)
12,000 Miles (20 000 km)
Vehicles Without Engine Oil Life System Only:
Change engine oil and filter (or every 12 months,
or every 600 hours of engine operation,
whichever occurs first). (2)
Vehicles With Engine Oil Life System Only:
Check oil life system (or every 12 months, or
every 600 hours of engine operation, whichever
occurs first). If engine oil and filter are changed,
reset system. See Engine Oil Life System
on page 190. (2) (8)
15,000 Miles (24 000 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.
270
Chassis lubrication service (or every 6 months,
whichever occurs first). (10)
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).
Steering system service. (11)
Front and rear suspension service. (12)
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).