2002 GMC Sonoma Owner's Manual - Page 423

Long Trip/Highway Scheduled Maintenance j For Two-Wheel-Drive vehicles only: Clean and repack the front wheel bearings (or at each brake relining, whichever occurs first). j Change 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 90_F (32_C) or higher. - In hilly or mountainous terrain. - When doing frequent trailer towing. - Uses such as found in taxi, police or delivery service. If you do not use your vehicle under any of these conditions, change the fluid and filter every 50,000 miles (83 000 km). Rotate tires. See "Tire Inspection and Rotation" in the Index for proper rotation pattern and additional information. (See footnote +.) Inspect engine accessory drive belt. An Emission Control Service. 4.3L V6 Engine Only: Replace fuel filter. An Emission Control Service. (See footnote [.) Replace engine air cleaner filter. An Emission Control Service. j j j j 7-39