Blue Bird VISION 2011 Driver'S Handbook Manual Download

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r o u t i n e

o p e r a t i o n

Transmission indicator lights

The instrument panel contains two indicator lights amd one priority message associ-
ated with the transmission:

range inhibited (priority message).

Under certain operating conditions, the Trans-

mission Control Module (TCM) may restrict gear selection to protect the engine /
transmission from damage. For example, if a downshift would cause the engine to
over-rev, the transmission may not respond to a change at the shift lever until engine
RPM decreases. When this occurs, the RANGE INHIBITED warning will appear in the
message display center. See the Range Inhibited Light and Shift Inhibits section of
the Allison Transmission operator’s manual for more information.

check Transmission.

While driving, be alert to any abnormal shifting, unusual sounds

or vibrations, smells, or frequent illumination of a transmission priority message. If
you experience any of these, get service immediately.

Transmission Temperature.

An oil temperature readout in the message display

center of the instrument panel indicates the transmission oil temperature. Extended
operations at low vehicle speeds with the engine at full throttle can cause excessive
oil temperatures. These temperatures may overheat the engine cooling system and
lead to engine and/or transmission damage.

If excessive temperature is indicated by the engine coolant temperature gauge,

stop the vehicle and check the cooling system. If the cooling system appears to be
functioning properly, shift to neutral and accelerate the engine to 1,200–1,500 rpm.
This will reduce the transmission temperature to operating level within two or three
minutes. If high temperature persists, stop the engine and have the overheating con-
dition investigated by service personnel.

If the transmission oil temperature readout indicates excessive temperature,

check the oil level in transmission (refer to the Oil Check Procedure in your Allison
Transmission Operator’s Manual). Stop the vehicle and shift to neutral. Accelerate the
engine to 1,200–1,500 rpm. The temperature should return to normal within two or
three minutes before the vehicle resumes operation. Normal temperature for both
on and off-highway operation is 160° to 200° F. Oil temperature should never exceed
250° F. If the sump oil temperature reaches 250° F, the TCM will inhibit operation in
the higher gears and turn on a priority message in the message display center indi-
cating high transmission temperature.

If high temperature in either engine or transmission persists, stop the engine and

have the overheating conditions investigated by maintenance personnel.

[CAUTION]

The engine should never be operated for more than 30 seconds

at full throttle with the transmission in gear and the vehicle not moving.
Prolonged operation of this type will cause the transmission oil temperature
to become excessively high and will result in damage to the transmission.