operators_manual

ratings are weight and speed limits that are
allowed while the vehicle is fully loaded (in
excess of the vehicle’
s standard GAWR)
and the axle is in its up position. Axle creep
ratings are assigned by the axle
manufacturer and are based on axle model
and intended service of the vehicle.
Contact an authorized dealership if you are
unable to identify the axle creep rating of
this vehicle.
• Liftable/steerable (axle lift
calibration required)
• Liftable/non-steerable (axle lift
calibration required)
• Non-liftable (some suspensions
require dump valve calibration)
WARNING
DO NOT operate or park the vehicle
with auxiliary axles in the down/loaded
position when vehicle is unladen, or is
being unloaded. Raise or dump air into
driver controlled auxiliary axle(s) prior
to unloading vehicle. Failure to do so
can result in loss of vehicle control or
roll-away that may result in personal
injury, property damage or death.
Auxiliary Axle Pressure Regulator
V
ehicles with liftable auxiliary axles will
have knobs available to adjust the
pressure in the auxiliary axle suspension.
These knobs are in addition to the tag and
pusher axle switches that control the axle
position.
Adding more pressure to the auxiliary axle
will increase the pressure the auxiliary axle
pushes down. Increasing pressure will
decrease load on the drive axles and will
decrease traction. Decreasing pressure will
transfer more weight to the drive axles and
will result in more traction from the drive
axles.
Deflate the auxiliary axle suspension
before coupling or uncoupling a trailer.
After the trailer is coupled or uncoupled,
then increase pressure to balance traction
and axle load requirements. Inflate air
springs of the auxiliary axles to the desired
pressure after coupling to a loaded trailer
while still maintaining proper traction of the
drive axles.
Adjust the pressure regulator control knob
to a lower pressure until desired traction is
obtained. By reducing air pressure at
pusher or tag axle, load will be transferred
to drive axles. Do not overload drive axles.
Always deflate air springs of the auxiliary
axles before attempting to unload vehicle.
DRIVING - Axle and Suspension
they are in the deployed (down) position.
There are different configurations of axles
with different functionality (liftable versus
steerable). Without the extra axle, the
excessive weight can reduce the service
life of vehicle components such as, but not
limited to, the frame rail, axles, suspension
and brakes.
Operation of the auxiliary axles includes
the proper maintenance of the system and
calibration of its controls. Operating the
auxiliary axles will also require a firm
understanding of the Gross Axle Weight
Rating (GAWR) and the load that is being
carried.
The vehicle will have switches on the dash
to control the position of the auxiliary axles.
In certain situations, however, the system
will override the controls to protect the axle
system. For Self Steering Lift Axles, the
axle will raise when the park brakes are
applied or if the vehicle is placed in
reverse. For Non-Steer Lift Axles, the axle
will only automatically raise if the park
brakes are applied and there are no park
brakes on the lift axle. Non-Steer Lift Axles
do not automatically raise when the vehicle
is placed in reverse.
Operating the auxiliary liftable axles must
be performed in a manner that does not
exceed the axle creep rating. Axle creep
Y53-6096-1C1 (09/20) 125
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