2003 GMC Sierra 1500 Pickup Owner's Manual - Page 108

Starting and Operating Your Vehicle New Vehicle Break-In Nofice: Your vehicle doesn't need an elaborate "break-in." But it will perform better in the long run if you follow these guidelines: e Ignition Positions With the key in the ignition switch, you can turn it to four different positions. C Keep your speed at 55 mph (88 k d h ) o less for r the first 500 miles (805 km). Don't drive at any one speed fast or slow - for the first 500 miles (805 km). Don't make full-throttle starts. Avoid making hard stops for the first 200 miles (322km) or so. During this time your new brake linings aren't yet broken in. Hard stops with new linings can mean prematurewear and earlier replacement. Follow this breaking-in linings. guideline every time you get new brake Don't tow a trailer during break-in. "Towing See a Trailer" in the Index for more information. e - e e A (LOCK): This position locks your ignition and manual transmission. It's a theft-deterrent feature. You will only be able to remove your key when the ignition is turned to LOCK. 2-2 1