1996 GMC Suburban Owner's Manual - Page 356

I Short Trip/City Maintenance Schedule-- Gasoline Engines I Uses such as found in taxi, police or delivery service. 100,000 Miles (166 000 km) (Continued) 0Change automatic transmission fluid and filter if the vehicle is mainly driven under one or more of these conditions: - - In heavy city traffic where the outside temperature regularly reaches90 F (32°C) or higher. O 0Inspect Positive Crankcase Ventilation ( P c v ) valve. An Emission Control Servicr. - In hilly or mountainous terrain. - When doing frequent trailer towing. DATE ACTUAL MILEAGE SERVICED B Y 7-28