DD15 Operator Guide – Engine Brake Operation

Engine Brake Operation

The engine brake system depends on a full-pressure flow of warm engine lubricating oil for proper lubrication of moving parts and optimum performance.‪


Always allow the engine to reach full normal operating temperature before activating the engine brake system to ensure positive engine brake engagement.‪



To avoid injury from loss of vehicle control, do not activate the Engine Brake system under the following conditions:‪

  • On wet or slippery pavement, unless the vehicle is equipped with ABS (anti-lock braking system) and you have had prior experience driving under these conditions.
  • When driving without a trailer (bobtailing) or pulling an empty trailer.
  • If the tractor drive wheels begin to lock or there is fishtail motion after the Engine Brake is activated, deactivate the brake system immediately if this occurs.

Under normal driving conditions the engine brake system is left in the ON position. However, this should change if roads become wet or slippery.‪

After it is switched on, the engine brake system is automatically activated each time you remove your feet completely from the clutch pedal and accelerator pedal. The engine brake automatically deactivates itself when you press the clutch pedal while shifting gears.‪


Do not attempt to “double clutch” the transmission while the engine brake system is turned on. Shifting gears without pressing the clutch or using the engine brake to reduce engine rpm may result in serious powertrain damage.‪

Note: Some systems may be programmed to activate themselves only when the brake pedal is pressed, so read your vehicle owner’s manual thoroughly to find out if you have this option.

EPA07 DD15 Operator’s Guide – DDC-SVC-MAN-0003
Generated on 10-13-2008