Four-Wheel Steering. Four-wheel steering is accomplished by using both the
steering wheel and the REAR AXLE STEERING Control Switch (48, Figure 5-1). Depending upon
which direction the operator wishes to travel, the steering wheel is turned in the same direction of
the REAR AXLE STEERING Control Switch (48) position. This method of steering allows the crane
to turn or maneuver in close, restricted areas.
Crabbing is also accomplished by using both the steering wheel and the REAR
AXLE STEERING Control Switch (48, Figure 5-1). Depending upon which direction the operator
wishes to travel (crab), the steering wheel is turned in the opposite direction in which REAR AXLE
STEERING Control Switch (48) is positioned. This method permits driving the crane forward or in
reverse at an angle from straight ahead in the crabbing manner.
Automatic Mode. The Automatic Powershift Control (APC) will automatically shift
up to the gear selected on the gear selector at the proper shift point as determined by its
sensors. The APC will also downshift and, engage and disengage torque converter lockup at the
proper time. Although the APC determines the shifting pattern, having a good knowledge of
proper shifting procedures is required for manual override operation APC 100 Override Switch (11,
Figure 5-1). Note that the APC100
is active when driving from the carrier cab only. When driving
from the superstructure cab, the transmission must be manually shifted.
None of the protective devices designed to protect
the drive train are in effect when operating in the
manual mode. Do not downshift to a lower gear if the
crane is traveling at a speed greater than the
maximum speed of the lower gear. Also, do not shift
from forward to reverse without completely coming to
a stop and do not speed up beyond second gear with
the vehicle in four-wheel drive (or with differential
In the early stages of shifting, keep the engine rpm down to the actual power
requirement, but anticipate the next shift demand so that the engine does
not labor with the next upshift.