Note:
Engine speed has a major influence of retarding performance.
When engine speed is maintained at the maximum allowable level, the
exhaust brake will operate at peak performance.
WARNING:
The exhaust brake is not recommended for use on
slippery or low traction road surfaces. Under these conditions a
loss of vehicle control could occur.
Exhaust brake operating characteristics
When you remove your feet from both the accelerator and clutch pedals
and the exhaust brake switch is in the on position, the exhaust brake is
activated. The following conditions should exist if the brake is operating
properly:
•
A slight change in the sound of the engine when the exhaust brake is
activated.
•
Engine temperature remains in the normal operating range.
•
Road speed usually decreases when the exhaust brake is applied
during a descent, except when the vehicle is carrying a heavy load or
the grade is extremely steep. In these instances, you may need to
apply the service brakes occasionally.
•
During a descent, the tachometer usually shows a drop in RPM
depending on the grade and the vehicle load.
•
Do not expect a retarding effect similar to sudden hard application of
the service brakes. The exhaust brake retards the vehicle with a
smooth braking effect.
•
Depending on the grade and vehicle load, you may or may not feel the
retarding force acting against your body when the brake is applied.
The brake’s retarding force is actually preventing the vehicle from
going much faster.
•
Engine speed has a major effect on retarding performance, with higher
engine speeds permitting greater retarding ability.
•
Engine brake performance is closely related to the type of
transmission your vehicle is equipped with. Downshifting of manual
transmission to the lowest gear possible, without exceeding the
maximum engine RPM limit, will maximize retarding performance.
Exhaust brakes will operate effectively with automatic transmissions,
but performance will vary with engine speed and the gear selected by
the transmission.
Make sure the exhaust brake is turned off before shutting off the engine.
2009 F-650/750
(f67)
Supplement
USA
(fus)
Driving
113
