Operating Down a Long, Steep Grade
Extra caution should be taken when operating a vehicle down a long steep grade. Failure to keep the vehicle within safe control speed limits while descending a grade may result in vehicle or property damage or both.
During operation of the vehicle, the operator should limit the engine speed to 1900 rpm or less. No extra engine power is achieved at engine speeds above 1900 rpm. Shifting gears without pressing the clutch, or using the engine brakes to reduce engine speed, may result in serious powertrain damage due to higher engine speeds. Never exceed 2000 rpm as higher engine speeds may result in extensive engine damage.
Any engine overspeed (engine speed exceeds 2500 rpm) while the vehicle is moving (vehicle speed over 0 MPH) is considered to be an operator-induced engine overspeed. Any mechanical engine failure within 3218 km (2000 mi) of an operator-induced engine overspeed event will not be eligible for Detroit warranty coverage.
Operate the engine brakes when descending a long, steep grade as follows:
- Before beginning the descent, determine if the brake system is operating properly by briefly depressing the accelerator pedal. The operator should be able to feel the system activate.
- Ensure the engine brake is in the appropriate power position (LOW/MED/HIGH).
- Do not exceed the safe control speed of the vehicle. Example: An operator could descend a 6% grade, under control only at 16 kph (10 mph) without an engine brake, but at 40 kph (25 mph) with an engine brake. Do not descend that same hill at 80 kph (50 mph) and still expect to remain under control. Operators should get to know how much slowing power the engine brakes can provide. Operators should get to know the engine brake system before climbing hills and should not exceed a safe control speed.
- Check the engine brake status often for proper position (LOW/MED/HIGH) since road conditions can change quickly. Never skip a step when operating the engine brake system. Always go from OFF to LOW and then to a higher position.
Caution: BRAKE FADE
To avoid injury, do not over apply the vehicle service brakes when descending a long, steep grade. Excessive use of the vehicle brakes will cause them to heat up, reducing their stopping ability. This condition, referred to as “brake fade”, may result in loss of braking, which could lead to personal injury or vehicle/property damage or both.
Warning: PERSONAL INJURY
Failure to keep the vehicle within safe control speed limits while descending a grade may result in loss of vehicle control, which could cause personal injury.