freightliner S2 Operator's Manual page 82

NOTICE
The differential lock should be engaged when the
vehicle is stopped or moving at a low, constant
speed and the wheels are not spinning, slipping,
or losing traction. Engagement at high speed or
power can damage the axle(s).
Do not permit rear wheels to spin freely for more
than ten seconds when traction is lost. Shift into
lock to prevent damage to interaxle and main
differentials.
Lock the wheels only when the vehicle is standing
still or moving at very low speed, less than 5 mph (8
km/h). Never lock the wheels when the vehicle is
traveling down steep grades or when the wheels are
slipping.
NOTE: On some vehicles, the differential lock
system is connected through the low speed
range of the transmission. If this system is used,
the transmission must be in the low speed
range for the wheels to fully lock.
WARNING
A vehicle with locked wheels can still slip side-
ways, causing possible loss of vehicle control,
personal injury, and property damage.
Be especially careful when driving under slippery
conditions with the wheels locked. Though forward
traction is improved, the vehicle can still slip side-
ways.
If the vehicle is moving, maintain a constant vehicle
speed when the differential lock is turned on. Briefly
let up on the accelerator to relieve torque on the
gearing, allowing the wheels to lock completely.
When the wheels are fully locked, the turning radius
will increase because the vehicle understeers. See
Fig. 11.2. Drive cautiously and do not exceed 25
mph (40 km/h).
To disengage the differential lock after leaving poor
road conditions, press the upper half of the switch,
while maintaining vehicle speed. Let up momentarily
on the accelerator to allow the wheels to fully unlock,
then resume driving at normal speed.
NOTE: If the differential lock system is con-
nected with the transmission in its low speed
range, shifting out of the low speed range will
02/09/96
A. Turning Radius When the Differential Lock is
Engaged (understeer condition).
B. Turning Radius When the Differential Lock is
Disengaged.
Fig. 11.2, Turning Radii
also disengage the differential lock function. The
switch will blink until the wheels unlock, and
then go out.
Drive Axles
A
B
f350079a
11.2