1997 GMC Sonoma Owner's Manual - Page 328

I Short TripKity Maintenance Schedule I 0Check readfront axle fluid level and add fluid as needed.Check constant velocity joints and axle seals for leaking. (See footnote **.) 0Rotate tires. See "Tire Inspection and Rotation" in the Index proper rotation for pattern and additional information. (See footnote +.) 42,000 Miles (70 000 km) 0Change engine oil and filter (or every 3 months, whichever occurs first). An Emission Control Service. 0Lubricate chassis components (or every 3 months, whichever occursfirst). (See footnote #.> ~~ ACTUAL MILEAGE SERVICED B Y 7-18