Owner`s manual
CHASSIS INFORMATION — 10
216
2008 KNIGHT
EXHAUST BRAKE
The exhaust brake (auxiliary
braking system) is designed
to supplement the standard air
brake system. Attached directly
to the engine turbocharger,
the exhaust brake system and
is not designed to bring the
motorhome to a complete
stop; however, it can assist in
controlling the speed of the
motorhome. Use of the exhaust
braking system can extend the
service life of pads, shoes, rotors and drums.
Operation
A switch on the driver’s console
operates the exhaust brake. The
exhaust brake will operate when
the switch is on and the throttle is
released.
Functions
When the exhaust brake is activated, a apper
inside the exhaust brake moves and restricts the
ow of exhaust gases. This causes an increase
of exhaust pressure within the engine. Increased
exhaust pressure slows engine speed. The
amount of engine braking power developed is
related to engine speed (RPM), so the engine
braking effect increases with higher engine
RPM.
The exhaust brake is wired to the electronically
controlled transmission. Use the exhaust brake
when descending a hill or off ramp. When the
exhaust brake is activated the transmission
automatically optimizes downshifts, utilizing the
gear selected to maximize the effectiveness of
the exhaust brake.
Certain road conditions and engine speeds
may require manually shifting the transmission
in order to generate adequate engine RPM and
increase the engine brake effect.
NOTE
The exhaust brake is designed to
supplement the service brakes. The
exhaust brake will not bring the
motorhome to a stop. Use of the exhaust
brake can help increase the service life
of the service brakes.
NOTE
Activating the exhaust brake does not
cancel cruise control.
NOTE
Idle the engine three to five minutes at
approximately 1000 RPM to warm the
engine before activating the exhaust
brake.
TRANSMISSION
The Allison World transmission incorporates
the World Transmission Electronic Control
(WTEC) system. The system is compromised
of ve major components connected by a
wiring harness: the Electronic Control Unit
(ECU), engine throttle position sensor, three
speed sensors, remote shift selector (keypad)
and the control module. The ECU processes
information received from the throttle position
sensor, speed sensor, pressure switch and shift
selector to provide optimum shift quality. This
is accomplished by matching transmission and
engine RPM during a shift to establish a desired
shift prole within the ECU. Another feature
of the transmission is the ability to “learn” or
“adapt.” The electronic control system optimizes
shift quality by using “Adaptive Shifting.”
A wide variety of varied shift conditions
is required before optimizing shift quality.
Generally, ve typical shifts of a consistent shift
type are needed to optimize shift quality.
Shift Selector
The keypads on the shift
control are R (Reverse),
N (Neutral), D (Drive),
Arrow up, Arrow down,
Mode button. A digital
display window shows
gear selection, various
transmission modes, oil
level and transmission
fault codes. Generation 4
keypads have a split screen
displaying two number sets while in drive. The
left number displays the highest forward range
available. The right number is the range that the
transmission is currently in. NN (Neutral) will
appear in the display window when the ignition
is turned On. This indicates the transmission is
in neutral and it is safe to start the crank. If the
NN does not display when the ignition is turned
on, there is no power to the shift selector and the
transmission will not allow the engine to start.
080355g
090392b
080498m