1995 GMC Sonoma Owner's Manual - Page 182

Driving On Grades Reduce speed and shift to a lower gear bcfbr-c? you start down a long or steep downgrade. If you don't shift down, you might have to use your brakes so much that they would get hot and no longer work well. On a long uphill grade, shift down and reduce your speed to around 45 lnph (70 km/h) to reduce the possibility of engine and transmission overheating. When towing at high altitude on steep uphill grades, consider the following: Engine coolant will boil at a lower tcmperature than at normal altitudes. If you turn your engine off immediately after towing at high altitude on steep uphill grades, your vehicle may show signs similar to engine overheating. To avoid this, let the engine run whilc parked (preferably on level ground) with the automatic transmission i n PARK (P) (or the manual transmission out of gear and the parking brake applied) fora few minutes before turning the engine off.If you do get the overheat warning, see "Engine Overheating" in the Index. Parking on Hills You really should not park your vehicle, with a trailer attached, on a h i l l . If something goes wrong, your rig could start t o move. People can be injured, and both your vehicle and the trailer can be damaged. But if you ever have to park your rig on a hill. here's how to do it: 1. Apply your regular brakes, but don't shift into PARK (P) yet, or into gear for a manual transmission. When parking uphill, turn your wheels away from the curb. When parking downhill, turn your wheels into the curb. 2. Have someone place chocks under the trailer wheels. 3. When the wheel chocks are i n place, release the regular brakes until the chocks absorb the load. 4. Reapply the regular brakes. Then apply your parking brake, and then shift into PARK (P), or REVERSE (R) for a manual transmission. 5. If you have a four-wheel-drive vehicle with a manual transfer case shift lever, be sure the transfer case is in a drive gear - not i n NEUTRAL (N). 6. Release the parking brake. 4-48