vehicle speed continues to increase, the DDEC® system will increase the engine
brake's braking power progressively. When the vehicle returns to the set cruise
speed the engine brake will turn off.
Engine Brake Operation
Always allow the engine to reach full normal operating temperature before
activating the engine brake system to ensure positive engine brake engagement.
The engine brake system depends on a full-pressure flow of warm engine
lubricating oil for proper lubrication of moving parts and optimum performance.
The minimum operating speed for the engine brake is 900 rpm. A Check Engine
Indicator will be illuminated when the predetermined high engine speed is
exceeded.
Under normal driving conditions the engine brake system can be left in the ON
position. However, this should change if roads become wet or slippery.
After being activated, the engine brake system is automatically activated each time
the accelerator pedal is depressed. The engine brake automatically deactivates itself
when the clutch pedal is pressed while shifting gears. Shifting gears without
pressing the clutch or using the engine brakes to reduce engine RPM may result in
serious powertrain damage due to higher engine speeds. Never exceed 2000 rpm as
these higher engine speeds may result in extensive engine damage.
Operating on Flat, Dry Pavement
Operate the engine brakes when driving on flat, dry pavement as follows:
1. If driving on flat, dry, open stretches with a light load and greater slowing
power is not required, the engine brake should be placed in the LOW
position.
2. If the service brakes are still needed, the engine brake should be moved to a
higher position until the need to use the service brakes to slow the vehicle
down is no longer present.
3. If carrying a heavier load and road traction is good, the engine brake should
be moved to the HIGH position.
4. Check the engine brake often for proper position since road conditions can
change quickly. Steps should never be skipped when operating the engine
brakes. Always go from OFF to LOW, and then to a higher position.
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.
Gen 5 DD Platform Operators Manual
All information subject to change without notice.
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DDC-SVC-MAN-0217
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