GMC Sierra Denali 2017 Owner's Manual page 444

Maintenance Schedule
Additional Required
Services - Severe
Rotate tires and perform Required Services.
Check engine oil level and oil life percentage.
Change engine oil and filter, if needed.
Replace passenger compartment air filter. (1)
Inspect evaporative control system. (2)
Replace engine air cleaner filter. (3)
Replace spark plugs. Inspect spark plug wires.
Change automatic transmission fluid and filter.
For GVW under 3 900 kg (8,600 lb), change
transfer case fluid, if equipped with 4WD. (4)
For GVW over 3 900 kg (8,600 lb), change
transfer case fluid, if equipped with 4WD. (4)
Drain and fill engine cooling system. (5)
Visually inspect accessory drive belts. (6)
Replace brake fluid. (7)
Footnotes Maintenance
Schedule Additional Required
Services Severe
(1) Or every two years, whichever
comes first. More frequent
replacement may be needed if the
vehicle is driven in areas with heavy
traffic, poor air quality, areas with
high dust levels or are sensitive to
environmental allergens. Filter
replacement may also be needed if
you notice reduced airflow, windows
fogging up, or odors. Your local GM
Service and Maintenance
Service location can help you
determine when it is the right time to
replace your filter.
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