GMC T-Series 2007 Owner's Manual page 301

❑ 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)
❑ Air compressor dry element pleated paper air
strainer service (or every 2 months, or every
800 hours, whichever occurs first).
❑ Thermostatically controlled engine cooling fan
service. (3) (17)
❑ Shields and underhood insulation
service. (3) (4) (18)
❑ Rear axle air shift motor service. (9)
❑ Air intake system service (or every 24 months,
whichever occurs first). (3) (4) (20)
48,000 Miles (75 000 km)
❑ Lubricate U-joints (or every 6 months,
whichever occurs first).
50,000 Miles (80 000 km)
❑ Inspect air compressor discharge port (or every
6 months or every 1,800 hours, whichever
occurs first.)
52,500 Miles (84 000 km)
❑ Check fluid levels (or every 3 months,
whichever occurs first). (1) (5)
❑ Chassis lubrication service (or every 6 months,
whichever occurs first). (10)
❑ 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).
301