1997 GMC Sonoma Owner's Manual - Page 321

Short Trip/City Maintenance Schedule 15,000 Miles (25 000 km) 0Change engine oil and filter (or every 3 months, whichever occurs first). An Emission Control Service. 0Check readfront axle fluid level and add fluid as needed. Check constant velocity joints and axle seals for leaking. (See footnote **.) 0For Two-Wheel-Drive vehicles only: Clean and repack the front wheel bearings (or at each brake relining, whichever occurs first). 0Lubricate chassis components (or every 3 months, whichever occurs first). (See footnote #.) 0Inspect air cleaner filter if you are driving in dusty conditions. Replace filter if necessary. An Emission Control Service. (See footnote?.) DATE ACTUAL MILEAGE SERVICED B Y 7-11