© 2020 Pierce Manufacturing Inc. All Rights Reserved. Driving the Vehicle / 5-47
OPERATION
5-27.3 Oshkosh 30000-Series All-Wheel Drive Transfer Case
The vehicle may be equipped with an (optional) Oshkosh 30000-Series all-wheel drive transfer case. This
configuration consists of a three-shaft, single-speed transfer case, full-time all-wheel drive, and is typically
configured to a 32% front, 68% rear torque split.
An inter-axle locking feature is available to lock the front and rear axles together for increased traction in poor
conditions. Refer to “Transfer Case Differential Lock (Oshkosh 30000-Series Transfer Case)” on page 5-47 for
operating instructions.
5-27.3a Transfer Case Differential Lock (Oshkosh 30000-Series Transfer Case)
The (optional) Oshkosh 30000-Series transfer case is equipped with an inter-axle (front to rear) locking function.
This will lock the transfer case differential to provide a constant 50% torque slit between the front and rear axles.
This may be used in conjunction with (optional) driver-controlled intra-axle locking differentials (side to side).
NOTE: The transfer case locking feature is for use in low-speed, poor traction conditions only. Disengage
the locking feature when leaving poor traction conditions and/or when vehicle speeds may increase
above 25mph.
Before
entering an area where poor traction conditions are likely to occur, engage the transfer case differential lock
prior to wheel slippage as follows:
1. At a speed of 25mph or below, activate transfer case differential lock-up switch, typically located on upper
console switch panel. Depending on options, this switch may be labeled Drive Line Lock Up or something
similar.
2. Let up on the accelerator, which provides an interruption in drive torque and facilitates the shift. An indicator
lamp may illuminate to indicate the locking operation has occurred successfully.
3. After conditions improve, let up on the accelerator, and then deactivate the transfer case locking feature using
the switch.
4. It may be necessary to slowly backup in order to disengage the system in event you can feel that the differential
has not disengaged.
5. Always unlock the transfer case lock after leaving adverse conditions. This permits the driveline to compensate
for differences in tire size and turning distances for each wheel, and will reduce stress on the drive line
components.
Do not engage transfer case differential lock when wheels are spinning freely. This can lead to loss of
control, resulting in a crash, and/or drive line damage.
Do not operate the vehicle on dry pavement with transfer case differential lock engaged. This could
lead to a crash. On dry pavement, you will not be able to steer well with a differential locked. The
transfer case differential lock should only be active when driving on surfaces with poor traction, such
as wet, slippery roads or loose gravel.
Do not use the transfer case differential lock during downhill operation or at speeds above 25 mph (40
km/h). If the transfer case differential lock is active under these conditions, your vehicle will exhibit
“understeer” handling characteristics. This “understeer” condition will cause your vehicle to not turn
as quickly and more steering effort will be required, which can cause a crash.
When the transfer case differential lock is disengaged, normal steering resumes.
To Next Page
Loading...
