Navistar WorkStar Series, Operator'S Manual

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Operation
NOTE: The “Down” indicator on the UP/DOWN switch signals
that the axle, controlled by that switch, is in the lowered position,
and is operational.
NOTE: The use of International Truck installed Lift Axles
provides improved vehicle load-carrying capability. However,
the lift axles do not increase the vehicle’s GVWR. The lift axle
system is made up of two axle types and the lift axle system
controls.
Lift Axle Locations
The vehicle can be equipped with as many as three lift axles.
The two lift axle designations are either a “pusher” or “Tag” axle,
as determined by its location. The “pusher” axle is one that is
mounted ahead of the rear driving axle(s), and a “tag” axle is
one that is mounted behind the last rear drive axle.
Lift Axle Types
WARNING
On systems with self-steering lift axles, the axle
will automatically rise to the UP position any
time the transmission is shifted into reverse, and
back down when the transmission is shifted out
of reverse. Before backing up, check to see that
area behind vehicle is clear of people, animals
and objects. Use a spotter whenever possible
and always keep that person in sight. Failure to
do so may result in property damage, personal
injury, or death.
The two lift axle designs are (1) “Fixed” (Rigid) and (2)
“Self-Steering” lift axles.
Fixed lift axle. The fixed lift axle design provides 20,000 pounds
maximum load carrying capacity. The design does not allow the
wheels to steer when cornering, thereby causing increased tire
wear due to tire scrubbing while cornering. The advantage of
this design is its simplicity, less components, which requires less
maintenance.
Self-Steering Lift Axle. The self-steering lift axle design
contains a spring-loaded self-centering mechanism that keeps
the axle tires tracking straight ahead with the vehicle’s straight
ahead movement.
When the vehicle is turned, the drag on
the tires, caused by cornering, causes the tires to steer in the
direction that creates the least rolling resistance. As the vehicle
direction straightens out, the self-centering mechanism returns
the tires to their straight ahead position. The advantage of this
design is the reduction in tire wear. The self-steering lift axle
provides 13,000 pounds of load carrying capacity.
The self-steering lift axles can only operate properly while the
vehicle is moving forward. Placing the truck in reverse while
the lift axle(s) is in the down position, will cause the axle to
automatically raised to the lifted (up) position.
The axle will
immediately return to the down position when the transmission
is shifted out of reverse.
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