2003 GMC Envoy Owner's Manual - Page 271

0 Know how to go uphill. You may wantto shift down to a lower gear. The lower gearshelp cool your engine and transmission, and you canclimb the hill better. Stay in your own lane when driving on two-lane or roads in hills or mountains. Don't swing wide cut across the center of the road. Drive at speeds that let you stay in your own lane. As you go over the topof a hill, be alert. There could be something in your lane, like a stalled car or an accident. You may see highway signs on mountains that warn of special problems. Examples are long grades, passing or no-passing zones, a falling rocks areaor winding roads. Be alertto these and take appropriate action. Coasting downhill inNEUTRAL (N) or with the ignition off is dangerous. Your brakes will have to do all the work of slowing down. They could get so hot that they wouldn't work well.You would then have poor braking or even none going down a hill. You could crash. Always have your engine running and your vehicle in gear when you go downhill. 4-38