GMC 2005 T-Series Owner's Manual page 256

150,000 Miles (240 000 km)
Cooling system service (or every 60 months since
last service, whichever occurs first). (2) (23)
Inspect engine drive belt; replace as necessary.
200,000 Miles (320 000 km)
Remove, disassemble, clean and inspect the air
brake trailer supply valve (or every 2 years, or
every 7,200 hours, whichever occurs first).
Inspect engine drive belt; replace as necessary.
250,000 Miles (400 000 km)
Rear axle service – Eaton, Rockwell, Spicer Axles
(or every 36 months, whichever occurs first). (24)
300,000 Miles (480 000 km)
Remove, disassemble, clean and inspect the air
brake air dryer (or every 3 years, or 10,800 hours,
whichever occurs first). Replace desiccant on
Bendix-Westinghouse units.
6-18
Footnotes
† = The U.S. Environmental Protection Agency or the
California Air Resources Board has determined that the
failure to perform this maintenance item will not nullify
the emission warranty or limit recall liability prior to
the completion of the vehicle's useful life. We, however,
urge that all recommended maintenance services be
performed at the indicated intervals and the
maintenance be recorded.
(1) = If your vehicle has an Allison automatic
transmission, your GM owner's manual is supplemented
by an Allison Transmission
refer to these manuals for related maintenance services.
(2) = An Emission Control Service.
(3) = A Noise Emission Control Device.
(4) = Applies only to vehicles sold in the United States.
(5) = Check fluid level in brake master cylinder,
power steering pump, axle, transmission and hydraulic
spring parking brake pump (if equipped). A low fluid
level in the brake master cylinder can indicate
worn brake linings and should be checked accordingly.
®
Operator's Manual. Always