GMC Duramax Diesel 2015 Owner's Manual page 108

Maintenance Schedule
Additional Required
Services - Normal
Rotate tires and perform Required Services.
Check engine oil level and oil life percentage.
Change engine oil and filter, if needed.
Replace engine air cleaner filter. (1)
Change automatic transmission fluid and filter.
Filter is external on pickups and internal on vans.
Change automatic transmission external filter -
pickup only.
Drain and fill engine cooling system. (2)
Visually inspect accessory drive belts. (3)
Replace brake fluid. (4)
Footnotes Maintenance
Schedule Additional Required
Services - Normal
(1) Or every four years, whichever
comes first.
(2) Or every five years, whichever
comes first. See Cooling System on
page 10-17.
Service and Maintenance
(3) Or every 10 years, whichever
comes first. Inspect for fraying,
excessive cracking, or damage;
replace, if needed.
(4) Or every 10 years, whichever
comes first.
11-5