2001 GMC Sierra 1500 Pickup Owner's Manual - Page 435

Scheduled Maintenance -- Gasoline Engines 22,500 Miles (37 500 km) 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: 25,000 Miles (41 500 km) j Allison Transmission Only: Change automatic transmission fluid and filters 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. DATE ACTUAL MILEAGE SERVICED BY: If you do not use your vehicle under any of these conditions, change the fluid and filter every 50,000 miles (83 000 km). 7-10