switch will blink until the wheels unlock, and
then go out.
Tandem Drive Axles With Interaxle
Lock
NOTICE
The interaxle lock should not be engaged on a
vehicle with obviously spinning wheels. Engage-
ment at high speed or power can damage the
axle(s).
Meritor has an interaxle lock (axle lock, interaxle dif-
ferential lockout) feature that is standard on all dual-
drive (tandem-drive) vehicles. Interaxle lock is recom-
mended for use under adverse road conditions
where greater traction is needed. See the axle manu-
facturer’s manual provided with the vehicle for more
information.
The interaxle lock switch (
) allows the driver
to lock both rear axles together. The red interaxle
warning light illuminates on the dash message center
when interaxle lock is engaged.
When the interaxle lock is not engaged, there is dif-
ferential action between the two axles. The differen-
tial compensates for different wheel speeds and
variations in tire size. Keep the interaxle lock disen-
gaged when driving on roads where traction is good.
When the interaxle lock is engaged, the differential
action between the two axles is locked. Both drive
axles now share the power. Both axles, and both
sets of wheels, turn together at the same speed. The
interaxle lock should be used when the vehicle en-
counters poor traction conditions; however, it also
increases drivetrain and tire wear and should be
used only when improved traction is required.
Interaxle Lock Switch
A two-position guarded rocker switch (
) con-
trols interaxle lock, causing both axle shafts to rotate
together. To lock the axles together, press the upper
half of the rocker momentarily (at the red LED). To
turn off interaxle lock, press the lower half of the
rocker (at the double-axle icon).
IMPORTANT: The interaxle lock rocker switch is
guarded to prevent unintentional switch activa-
tion. This switch does not have a diagnostic
blink function when inactive.
When the interaxle lock 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 interaxle lock is engaged. At this point, the LED
comes on steady and stays illuminated. In normal
operation, the interaxle may lock so quickly that the
blinking of the switch is barely noticeable.
If operation of the switch is not possible for any rea-
son (ignition is turned off, vehicle is moving too fast,
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 axles
lock together, or for a maximum of 10 seconds. 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 lock mechanism may not be fully
engaged/disengaged. Bring the vehicle to an autho-
rized Freightliner service facility for testing.
Interaxle Lock Operation
To engage interaxle lock and achieve maximum pull-
ing power in slippery or hazardous road conditions,
operate the interaxle lock switch as discussed above,
while maintaining vehicle speed. Let up momentarily
on the accelerator until the axle lock engages. Pro-
ceed over poor road conditions with caution. Do not
wait until traction is lost and the tires are spinning
before engaging the interaxle lock.
NOTICE
Do not turn on the interaxle lock switch when the
tires are slipping. Do not continuously operate
the vehicle with the interaxle lock engaged dur-
ing good road conditions. To do so could result
10/26/2001
f610595
Fig. 8.23, Interaxle Lock Switch
Drivetrain
8.31
