2011 Chevrolet Impala Owner's Manual - Page 252

9-44 Driving and Operating Parking on Hills 4. Reapply the brake pedal. Then apply the parking brake and shift the transmission into P (Park). 5. Release the brake pedal. Driving on Grades Notice: Do not tow on steep continuous grades exceeding 9.6 km (6 miles). Extended, higher than normal engine and transmission temperatures may result and damage the vehicle. Frequent stops are very important to allow the engine and transmission to cool. Reduce speed and shift to a lower gear before starting down a long or steep downgrade. If the transmission is not shifted down, the brakes might have to be used so much that they would get hot and no longer work well. On a long uphill grade, shift down and reduce the vehicle's speed to around 70 km/h (45 mph) to reduce the possibility of the engine and the transmission overheating. If the engine does overheat, see Engine Overheating on page 10‑21. { WARNING Parking the vehicle on a hill with the trailer attached can be dangerous. If something goes wrong, the rig could start to move. People can be injured, and both the vehicle and the trailer can be damaged. When possible, always park the rig on a flat surface. If parking the rig on a hill: 1. Press the brake pedal, but do not shift into P (Park) yet. Turn the wheels into the curb if facing downhill or into traffic if facing uphill. 2. Have someone place chocks under the trailer wheels. 3. When the wheel chocks are in place, release the brake pedal until the chocks absorb the load. Leaving After Parking on a Hill 1. Apply and hold the brake pedal while you: ... start the engine, shift into a gear, and release the parking brake. 2. Let up on the brake pedal. 3. Drive slowly until the trailer is clear of the chocks. 4. Stop and have someone pick up and store the chocks. Maintenance When Trailer Towing The vehicle needs service more often when pulling a trailer. See Scheduled Maintenance on page 11‑2 for more information.