2001 GMC Sierra 1500 Pickup Owner's Manual - Page 434

Scheduled Maintenance -- Gasoline Engines 7,500 Miles (12 500 km) j Drive axle service. If your vehicle is used to pull a trailer, a rear axle fluid j j change is recommended after a break-in period. Change the rear axle fluid after the first 500 miles (800 km) of trailer towing. See "Recommended Fluids and Lubricants" in the Index for the proper fluid to use. Check rear/front axle fluid level and add fluid as needed. Check constant velocity joints and axle seals for leaking. Rotate tires. See "Tire Inspection and Rotation" in the Index for proper rotation pattern and additional information. (See footnote +.) DATE ACTUAL MILEAGE SERVICED BY: 15,000 Miles (25 000 km) j If Equipped: Replace passenger compartment air filter. If you drive regularly under dusty conditions, the filter may require replacement more often. j Check rear/front axle fluid level and add fluid as needed. Check constant velocity joints and axle seals for leaking. j Rotate tires. See "Tire Inspection and Rotation" in the Index for proper rotation pattern and additional information. (See footnote +.) DATE ACTUAL MILEAGE SERVICED BY: 7-9