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or illuminates during driving, it means that the 4WD
system is not functioning properly and that service is
required.
WARNING!
Always engage the parking brake when powering
down the vehicle if the(Service 4WD(light is
illuminated. Not engaging the parking brake may
allow the vehicle to roll which may cause personal
injury.
NOTE:Do not attempt to make a shift while only the
front or rear wheels are spinning. The NV 144 transfer
case is not equipped with a synchronizer and therefore
the front and rear driveshaft speeds must be equal for the
shift to take place. Shifting while only the front or rear
wheels are spinning can cause damage to the transfer
case.Proper operation of four-wheel-drive vehicles depends
on tires of equal size, type and circumference on each
wheel. Any difference in tire size can cause damage to the
transfer case.
Because four-wheel-drive provides improved traction,
there is a tendency to exceed safe turning and stopping
speeds. Do not go faster than road conditions permit.
For additional information on the appropriate use of each
transfer case mode position see the information below:
AW D
Normal All-Wheel-Drive High Range - Employs inter-
axle differential. Allows front and rear wheels to rotate at
different speeds. All road surfaces.
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vehicle in the 4LOCK position on dry hard surfaced
roads. This feature provides the safety, security, and
convenience of operating in all-wheel drive at all times
regardless of road conditions.
When additional traction is required, the 4LOCK and
4LO positions can be used to lock the front and rear
driveshafts together through the transfer case inter-axle
differential and force the front and rear wheels to rotate
at the same speed. This is accomplished by rotating the
4WD Control Switch to these positions. The 4LOCK and
4LO positions are intended for loose, slippery road
surfaces only. Driving in the 4LOCK and 4LO positions
on dry hard surfaced roads may cause increased tire wear
and damage to the driveline components.
The transfer case Neutral (N) position is selected by
depressing the recessed button located on the lower left
hand corner of the 4WD Control Switch.NOTE:The transfer case Neutral (N) position is to be
used for recreational towing only. See Recreational Tow-
ing section for specific procedures on shifting into and
out of Neutral (N).
Transfer Case Position Indicator Lights
Transfer case position indicator lights are located on the
instrument cluster. If there are no indicator lights on or
flashing the transfer case position is All-Wheel Drive
(AWD) and indicate the current and desired transfer case
selection (4HI,4LOCK).
The ªSVC 4WDº warning light monitors the electric shift
4WD system. If this light remains on after engine start up
or illuminates during driving, it means that the 4WD
system is not functioning properly and that service is
required.
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WARNING!
You or others could be injured if you leave the
vehicle unattended with the transfer case in the
Neutral (N) position without first fully engaging the
parking brake. The transfer case Neutral (N) position
disengages both the front and rear driveshafts from
the powertrain and will allow the vehicle to move
regardless of the transmission position. The parking
brake should always be applied when the driver is
not in the vehicle.
For additional information on the appropriate use of each
transfer case mode position see the information below:
AW D
Normal All-Wheel-Drive High Range - Employs inter-
axle differential. Allows front and rear wheels to rotate at
different speeds. All road surfaces.4LOCK
Four-Wheel-Drive LOCK - Locks the transfer case inter-
axle differential. Forces front and rear wheels to rotate at
the same speed. Additional traction for loose, slippery
road surfaces only.
4LO
Four-Wheel-Drive Low Range - Low speed 4 wheel
drive. Locks the transfer case inter-axle differential.
Forces the front and rear wheels to rotate at the same
speed. Additional traction and maximum pulling power
for loose, slippery road surfaces only. Do not exceed 25
mph (40 km/h).
N
Neutral - Disengages both the front and rear driveshafts
from the powertrain. To be used for flat towing behind
another vehicle. See Recreational Towing for more infor-
mation.
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Transfer Case
Inspect the transfer case for fluid leaks. If a fluid leak is
evident the transfer case fluid level may be low. Have the
transfer case serviced immediately.
CAUTION!
Damage may result from operation of the vehicle
with low transfer case fluid.
The transfer case fluid should be drained and refilled at
the intervals specified.
Lubricant Selection
Refer to Recommended Fluids, Lubricants and Genuine
Parts for correct fluid type.
Axles
Refer to Recommended Fluids, Lubricants and Genuine
Parts for correct fluid type.
The manufacturer does not recommend regularly sched-
uled oil changes for axles in vehicles whose operation is
classified as normal truck service.
NOTE:The presence of water in the gear lubricant will
result in corrosion and possible failure of differential
components. Operation of the vehicle in water, as may be
encountered in some off-highway types of service, will
require draining and refilling the axle to avoid damage.
Rear Axle
Rear Axle fluid levels should be 7/89(22 mm) below the
fill plug hole for 8 1/49axles, and 1 5/89(41 mm) below
the fill plug hole for 9 1/49axles.
MAINTAINING YOUR VEHICLE 319
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