GMC Sierra Owners Manual
New Vehicle Break-In
Notice: The vehicle does not need an elaborate break-in. But it will perform better in the long run if you follow these guidelines:
• Keep the vehicle speed at 88 km/h (55 mph) or less for the first 805 km (500 miles).
• Do not drive at any one constant speed, fast or slow, for the first 805 km (500 miles). Do not make full-throttle starts. Avoid downshifting to brake or slow the vehicle.
• Avoid making hard stops for the first 322 km (200 miles) or so. During this time the new brake linings are not yet broken in. Hard stops with new linings can mean premature wear and earlier replacement. Follow this breaking-in guideline every time you get new brake linings.
• Do not tow a trailer during break-in. See Trailer Towing on page 9‑84 for the trailer towing capabilities of the vehicle and more information.
Following break-in, engine speed and load can be gradually increased.