2004 GMC Sierra 1500 Pickup Owner's Manual - Page 543

Additional Required Services (cont'd) Service Allison transmission only: Change automatic transmission fluid and filter (severe service). See footnote (m). Allison transmission only: Change automatic transmission fluid and filter (normal service). Except Allison: Change automatic transmission fluid and filter (severe service).See footnote (h). Except Allison: Change automatic transmission fluid and filter (normal service). Four-wheel drive with automatic transfer case only: Change transfer case fluid. See footnote (g). Inspect evaporative control system. An Emission Control Service. See footnotes † and (k). 25,000 (41 500) • 50,000 (83 000) • 75,000 (125 000) • 100,000 (166 000) • 125,000 (207 500) • 150,000 (240 000) • • • • • • • • • • • • • • 6-7