in damage to the axle gearing and excessive tire
wear.
To disengage the interaxle lock after leaving poor
road conditions, operate the interaxle lock switch as
discussed above while maintaining vehicle speed.
Let up momentarily on the accelerator to allow the
axles to fully unlock, then resume driving at normal
speed.
Axle Shift
NOTICE
To prevent transmission and axle damage, make
sure the automatic transmission is in high range
when performing an axle shift with the vehicle
moving.
Axle shift is a function installed on vehicles with two-
speed axles to allow the use of the low speed range
when greater traction and maximum pulling power is
needed at low engine speed (rpm).
Under normal operating conditions, the vehicle is op-
erated using the high-speed gear ratios of the axle.
Under extreme weather or off-road conditions, at low
speed and rpm and/or to pull heavy loads, the ve-
hicle must be operated using the low-speed, or re-
duction, gear ratios of the axle.
Axle Shift Switch
The axle shift switch is a two-position guarded rocker
switch (
) installed on vehicles with two-
speed axles.
To shift the axle from low speed to high speed, press
the upper half of the rocker momentarily (at the
LED). To turn the axle shift off (switch from high
speed back to low speed), press the upper half of
the rocker again. When the axle has shifted speed,
the LED turns off.
When the panel lights are on, the AXLE SHIFT leg-
end is backlit in green.
IMPORTANT: The axle shift rocker switch is
guarded to prevent unintentional switch activa-
tion. If the LED in the switch begins to blink dur-
ing normal operation, when the switch has not
been activated, this indicates an error condition.
Bring the vehicle to an authorized Freightliner
service facility as soon as possible.
When the axle shift switch is pressed, three re-
sponses are possible: a normal response, a slow re-
sponse, and an abnormal response.
Normal Response:
The LED in the switch blinks until
the axle shifts speed. At this point, the LED comes
on steady and stays illuminated. In normal operation,
the axle may shift so quickly that the blinking of the
switch is barely noticeable.
If operation of the switch is not possible for any rea-
son (interaxle lock is on, ignition is turned off, etc.),
the LED will stop blinking and turn off.
Slow Response:
If operation of the switch is slowed
for any reason (by cold weather, low air pressure,
etc.), the switch will continue to blink until the axle
shifts. As in the normal response, the LED comes on
steady and stays illuminated.
Abnormal Response:
If the LED blinks for more than
30 seconds, the axle shift function/mechanism may
not be operating correctly. Bring the vehicle to an
authorized Freightliner service facility for testing.
Axle Switch Interlock
NOTE: On vehicles with tandem drive axles,
there is an interlock that prevents an axle from
shifting speed whenever the interaxle lock is on.
If the axle shift switch is pressed when the interaxle
lock is on, the axle shift will not be completed. The
LED does the following:
•
If the LED is off, the LED comes on briefly and
turns off again.
•
If the LED is on, it stays on.
To complete the axle shift, turn off the interaxle lock
and press the axle shift switch again. If still needed,
the interaxle lock can then be reactivated.
10/26/2001
f610594
Fig. 8.24, Axle Shift Switch
Drivetrain
8.32
