1997 GMC Suburban Owner's Manual - Page 218

Hill and Mountain Roads If you drive regularly in steep country, or if you're planning to visit there, here are some tips that can make your trips safer and more enjoyable. (See "Off-Road Driving" in the Index for information about driving off-road.) Keep your vehicle in good shape. Check all fluid levels and also the brakes, tires, cooling system and transmission. These parts can work hard on mountain roads. 0 Know how to go down hills. The most important thing to know is this: let your engine dosome of the slowing down. Shift to a lower gear when you go down a steep or longhill. Driving on steep hills or mountains is different from driving in flat orrolling terrain.