ENGINE OPERATION - Operating Instructions The engine brake is NOT intended as the primary brake for the vehicle, nor is it an emergency brake. The engine brake only helps the service brakes by using pressure to slow the drivetrain. Use the service brakes for quick stops. 1 WARNING NOTE DO NOT use an exhaust brake when driving bobtail or with an unloaded trailer. There may not be enough weight on the rear axle to provide trac- tion. This could cause a loss of control and jackknife resulting in an injury ac- cident. Make sure the exhaust brake is switched “OFF” when bobtailing or with an unloaded trailer. Failure to comply may result in death, personal injury, equipment or property damage.
Once you have determined what the safe speed is for your vehicle, operate the engine brakes with the transmis- sion in the lowest gear that will not cause the engine speed to exceed the rated engine speed. The optimum braking power of the engine brakes is reached at rated engine speed. Cor- rect gear selection, therefore, is criti- cal. Braking Truck on Grade The selector switch can be used to vary braking power as road conditions change. Vehicle service brakes must be used when additional braking power is required. CAUTION Never exceed governed engine speed because engine damage can occur.
Operating engine beyond the gov- erned speed causes additional strain on valve train and internal engine com- ponents. Operate the engine within governed engine speed. Slow Down Around Curves 25 MPH Y53-1166-1G1 (08/2018) 25