Navistar WorkStar Series, Operator'S Manual

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Operation
• The gear display on the shift selector will stop blinking
when the downshift is completed, and the driver will notice
resumption of engine braking as an indication that the shift
is completed.
When the transmission is in manual mode, engine protection
upshifts are disabled. This could result in an undesirable engine
overspeed condition. It is the operator’s responsibility to prevent
mechanical damage to the truck. Under these conditions, use
service brakes and select the appropriate gear, as required, to
keep the engine rpm within operating limits.
Automatic Transmission Operation
With the Allison transmission, when the engine brake is
activated, the transmission is programmed to perform shift
schedules that maximize braking effects.
The Allison transmission control module is programmed with a
pre-selected 4th gear as a default. This means that when the
driver selects “D” or Drive, the engine brake will operate down
to 4th gear (at or above 1,200 RPM). If the driver manually
selects 3rd or 2nd gear, the engine brake will operate down to
the manually selected gear (at or above 1200 RPM).
NOTE: Manually selecting 3rd or 2nd gear during braking with
no load or during slippery driving conditions could result in a
loss of traction, as indicated in the above warning. Manually
selecting 3rd gear or 2nd gear will not cause damage to the
engine or transmission. The manually selected gear is only for
driver intent. The transmission will only downshift according to
the pre-programmed shift schedules.
The engine brakes will deactivate when the transmission shifts
from converter lock-up to normal torque converter operation.
ABS Operation
When an ABS event occurs, the engine brake will turn OFF and
will automatically be turned back ON when the ABS conditions
are no longer present.
MaxxForce® Engine Features
The MaxxForce® engines are electronically controlled diesel
engines. The engine Electronic Control Module (ECM) monitors
and controls the injection process and other engine functions.
The ECM also communicates with the Body Controller (BC)
and alerts it to out-of-range operating conditions.
The BC
in turn, generates engine function indicators and warning
indicators. Since many of the engine performance features are
owner selectable and electronically programmable, some of the
operating parameters will vary from vehicle to vehicle. Some
of these standard and optional monitored engine operating
functions and warning indicators include:
Some standard features:
• Engine Warm-Up Control - (ECM) adjust injector operation
as required.
• Cold Ambient Protection (CAP) - to aid engine warm up and
maintain engine temperature.
• Cruise Control - provides vehicle speed control.
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