WARNING   WARNING:  Do not use tow/haul when the road surface is slippery. Failure to follow this instruction could result in the loss of control of your vehicle.
WARNING   WARNING:  Do not use diesel engine exhaust braking when the road surface is slippery. Failure to follow this instruction could result in the loss of control of your vehicle.

Note:   Installing an exhaust or auxiliary brake does not necessarily protect the engine from exceeding the maximum governed speed. Use the primary brakes to make sure the engine never exceeds the maximum governed speed under any circumstance.
Note:   Before starting the engine, make sure that the exhaust brake is off. Do not switch the exhaust brake on until the engine has reached normal operating temperature.
Note:   Engine speed has a major influence on limiting performance. When engine speed stays at the maximum allowable level, the exhaust brake operates at peak performance.
Note:   Exhaust brakes operate effectively with automatic transmissions. However, performance varies with engine speed and the gear selected by the transmission.
An exhaust brake is an auxiliary braking system that assists, but does not replace, the primary brake system. It helps control vehicle speed. It is not a vehicle-stopping device.
Use the button on the instrument panel, in combination with the accelerator pedal, to maximize the use of the exhaust brake in the following conditions:
  • Off-highway driving.
  • Mountain driving.
  • Heavy traffic.
  • High-speed highway driving.
Exhaust Brake Switch
To switch the exhaust brake on, press the button. A light on the instrument cluster indicates the system is on. Press the button again to switch it off.
While approaching a steep grade, make sure that the exhaust brake switch is on. The exhaust brake begins working as soon as you remove your foot from the accelerator pedal.
Before descending a hill or steep grade, always select the proper gear. If you take the transmission out of gear while descending, you may not be able to select another gear because of maximum governed RPM.
Make sure the engine speed does not exceed the maximum allowable engine RPM. Exceeding the maximum allowable engine RPM can result in damage to the engine. Apply the service brakes to reduce the engine RPM or make a slower descent by using a lower gear.
While driving down a grade, use a low enough gear to descend safely with a minimum application of the service brakes. As a general guideline, use the same gear as you use to ascend the hill.
Exhaust Brake Operating Characteristics
The exhaust brake switches on when you remove your feet from the accelerator pedal and the exhaust brake is on.
If the brake is working properly, you may notice:
  • A slight change in engine sound when the exhaust brake turns on.
  • A smooth braking effect. Do not expect a retarding effect similar to sudden, hard application of the service brakes.
  • A retarding force possibly felt acting against your body during brake application, depending on the grade and vehicle load. This force helps your vehicle resist increasing speeds down grades.
  • Engine temperatures remaining in the normal operating range.
  • A drop in engine RPM, depending on grade and vehicle load, during a descent.
  • A decrease in road speed when applying the exhaust brake during a descent, except when your vehicle is carrying a heavy load or the grade is extremely steep. In these instances, you may need to apply the service brakes occasionally.