1997 GMC Suburban Owner's Manual - Page 391

Long Tripmighway Maintenance Schedule -- Gasoline Engines I 50,000 Miles (83 000 km) 17 Vehicles With GVWR Above 8,500 lbs. Only: Inspect shields and underhood insulation for damage looseness. Adjust or or replace as required. This is a Noise Emission Control Service. Applicable only vehicles sold in to the United States. 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 reaches 90O F (32O C) or higher. - In hilly or mountainous terrain. - When doing frequent trailer towing. - Uses such as found in taxi, police or delivery service. I f you do not useyour vehicle under any these of conditions, the fluid andfilter do not require changing. Rotate tires. See "Tire Inspection and Rotation" in the Index for proper rotation pattern and additional information. (See footnote+.) DATE ACTUAL MILEAGE SERVICED BY: 7-35