GMC Sierra 2000 Owner's Manual page 357

Scheduled Maintenance
Long Trip/Highway Intervals
Every 50,000 Miles (83 000 km): Automatic
Transmission Service (vehicles over 8600 GVWR or
driven under severe conditions or equipped with
diesel engine).
Every 60,000 Miles (100 000 km): Engine Accessory
Drive Belt Inspection. 7.4L Gasoline Engine on
Complete Vehicle Over 14,000 GVWR and Chassis
Cabs Only: Fuel Tank, Cap and Lines Inspection.
If Equipped: Exhaust Gas Recirculation System
Inspection. Gasoline Engine Only: Evaporative
Control System Inspection. Diesel Engine Only:
Crankcase Depression Regulator Valve (CDRV)
System Check.
7-8
Long Trip/Highway Intervals
Every 100,000 Miles (166 000 km): Gasoline Engine
Only: Spark Plug Wire Inspection. Gasoline Engine
Only: Spark Plug Replacement. Gasoline Engine
Only: Automatic Transmission Service (normal
conditions). Gasoline Engine Only: Positive
Crankcase Ventilation (PCV) Valve Inspection.
Every 150,000 Miles (240 000 km): Cooling System
Service (or every 60 months, whichever occurs first).
These intervals only summarize maintenance services.
Be sure to follow the complete scheduled maintenance
on the following pages.