2006 GMC Yukon Owner's Manual - Page 115

Starting and Operating Your Vehicle New Vehicle Break-In Notice: Your vehicle does not need an elaborate break-in. But it will perform better in the long run if you follow these guidelines: Ignition Positions • Keep your speed at 55 mph (88 km/h) or less for the first 500 miles (805 km). • Do not drive at any one constant speed, fast or slow, for the first 500 miles (805 km). Do not make full-throttle starts. Avoid downshifting to brake, or slow, the vehicle. • Avoid making hard stops for the first 200 miles (322 km) or so. During this time your 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 Towing a Trailer on page 4-60 for the trailer towing capabilities of your vehicle and more information. Following break-in, engine speed and load can be gradually increased. Use the key to turn the ignition switch to four different positions. A (LOCK): This position locks the ignition and transmission. It is a theft-deterrent feature. You will only be able to remove the key when the ignition is turned to LOCK. Notice: Using a tool to force the key from the ignition switch could cause damage or break the key. Use the correct key and turn the key only with your hand. Make sure the key is all the way in. If it is, turn the steering wheel left and right while you turn the key hard. If none of this works, then your vehicle needs service. 2-19