1997 GMC Sonoma Owner's Manual - Page 317

I I Short TripKity Maintenance Schedule The services shown in this schedule up to 100,000 miles ( 166 000 km) should be performed after 100,000 miles (166 000 km) at the same intervals. The services shown at 150,000 miles (240 000 km) should be performed at the same interval after 150,000 miles (240 000 km). + A good time to check your brakes is during tire rotation. See "Brake System Inspection" under "Periodic Maintenance Inspection" in Part C of this schedule. ** Drive axle service (see "Recommended Fluids and Lubricants" in the Index for proper lubricant to use): a Locking Differential -- Drain fluid and refill at first See "Owner Checks and Services" and "Periodic Maintenance Inspections" following. Footnotes -f' The U.S. Environmental Protection Agency or the California Air Resources Board has determined that the failure to perform this maintenance item will not nullify the emission warranty or limit recall liability prior to the completion of the vehicle's useful life. We, however, urge that all recommended maintenance services be performed at the indicated intervals and the maintenance be recorded. ## Lubricate the 0 engine oil change. At subsequent oil changes, check fluid level and add fluid as needed. If driving in dusty areas ortowing a trailer, drain fluid and refill every 15,000 miles (25 000 km). Standard Differential -- Check fluid level and add fluid as needed at every oil change. If driving in dusty areas or towing a trailer, drain fluid and refill every 15,000 miles (25 000 kmj. heavy-duty or off-road use. a More frequent lubrication may be required for front suspension,ball joints, steering linkage and transfer case shift linkage, parking brake cable guides, propshaft splines, universal ioints and brake pedal springs. 7-7