2014 Chevrolet Express 3500 Passenger Owner Manual - Page 350

11-6 Service and Maintenance (7) 2500/3500 series vehicles only. For severe commercial use vehicles, see Special Application Services on page 11-8. Footnotes - Maintenance Schedule Additional Required Services - Normal (1) Check all fuel and vapor lines and hoses for proper hook-up, routing, and condition. (2) Or every four years, whichever comes first. (3) Do not directly power wash the transfer case output seals. High pressure water can overcome the seals and contaminate the transfer case fluid. Contaminated fluid will decrease the life of the transfer case and should be replaced. (4) Or every five years, whichever comes first. See Cooling System on page 10-17. (5) Or every 10 years, whichever comes first. Inspect for fraying, excessive cracking, or damage; replace, if needed. (6) Or every 10 years, whichever comes first.