1995 GMC Jimmy Owner's Manual - Page 200

When towing athigh altitude on steep uphill grades, consider the following: at If Engine coolant will boil a lower temperature than at normal altitudes. you turn your engine off immediately after towing at high altitude on steep to uphill grades, your vehicle may show signs similar engine overheating. To avoid this, let theengine run while parked (preferably on levelground) with the automatic transmission in PARK (P)(or the manual transmission out of gear and the parking brakeapplied) for a 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 hill. If be something goes wrong, yourrig could start to move. People can injured, and both your vehicle and the trailer can be damaged. a But if you ever have to park your rig on hill, here's how todo it: don't shift into PARK (P) yet, or into 1. Apply your regular brakes, but gear for a manual transmission. Then turn your wheels into the if curb facing downhill or into trafficif facing uphill. 2. Have someone placechocks under the trailer wheels. the 3. When the wheel chocks are in place, release the regular brakes until 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 transfercase shift lever, be sure the transfer case is in a drive gear - not in NEUTRAL (N). 6. Release the parking brake. 4-46