1995 GMC Yukon Owner's Manual - Page 377

Every 27,000 Miles (45000 km) Spark Plugs Replacement Every 50,000 Miles (83 000 km) Automatic Transmission Service Every 60,000 Miles (100 000 km) Spark Plug Wire Inspection Exhaust Gas Recirculation (EGR) System Inspection Fuel Tank, Cap and Lines Inspection Evaporative Emission Control System Inspection Electronic Vacuum Regulator Valve (EVRV) Inspection Schedule I Definition - Diesel Engines Follow Maintenance Schedule I if any one of these is true for your vehicle: Most trips are less than 5 to I O miles (8 to I6 km). This is particularly important when outside temperatures arebelow freezing. Most trips include extensive idling (such a s frequent driving in stop and go traffic). You operate y o ~ vehicle i n dusty areas or off-road frequently. ~r You frequently tow a trailer or use a carrier o n top of your vehicle. Schedule I should also be followed if the vehicle is used for delivery service. police. taxi, or other commercial application. 7-9