freightliner S2 Operator's Manual page 81

Drive Axles
Drive Axles, Detroit
™
Meritor
For additional information regarding Meritor axles,
visit the Meritor website at www.arvinmeritor.com.
Drive Axles With Differential Lock
The optional driver-controlled differential lock should
only be used under adverse road conditions where
greater traction is needed. With the differential lock
on, the turning radius is increased and vehicle han-
dling is affected. The red differential lock indicator
light illuminates on the dash message center when
the differential lock is engaged.
A differential lock provides maximum traction under
slippery conditions. When the differential lock is en-
gaged, the clutch collar completely locks the differen-
tial case, gearing, and axle shafts together, maximiz-
ing the traction of both wheels and protecting against
spinout. Do not exceed 25 mph (40 km/h) when the
differential lock is engaged.
Under normal traction conditions, do not use the dif-
ferential lock feature.
Differential Lock Switch
NOTICE
The differential lock should only be engaged
when the vehicle is stopped or moving slowly at
low throttle. This will prevent internal axle dam-
age.
A two-position guarded rocker switch controls the
differential lock. See Fig.
together, momentarily press the upper half of the
switch. To unlock the wheels, press the upper half of
the switch again.
IMPORTANT: The differential lock rocker switch
is guarded to prevent unintentional switch acti-
vation. If the light emitting diode (LED) in the
switch begins to blink during normal operation,
when the switch has not been activated, an
error condition exists. Bring the vehicle to an
authorized Freightliner service facility as soon
as possible.
11.1
™
and
11.1. To lock the wheels
10/26/2001
Fig. 11.1, Differential Lock Switch, Optional
When the differential lock switch is pressed, three
responses are possible: a normal response, a slow
response, and an abnormal response.
Normal Response: The LED in the switch blinks until
the axle has responded to the request to lock the
wheels. At this point, the LED remains illuminated
constantly. In normal operation, the wheels 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 faster
than 25 mph, etc.), the LED will stop blinking and
turn off.
Slow Response: If operation of the switch is slowed
for any reason (vehicle moving too fast, low air pres-
sure, etc.), the switch will continue to blink until the
wheels are able to lock. As in the normal response,
the LED remains illuminated when the differential
lock is engaged.
NOTE: If the vehicle is moving too fast, let up
slightly on the accelerator. As the vehicle slows,
the wheels will lock.
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.
Differential Lock Operation
WARNING
Locking the wheels when the vehicle is traveling
down steep grades or when the wheels are slip-
ping could damage the differential and/or lead to
loss of vehicle control, causing personal injury
and property damage.
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