JLG sky trak mmv Service Manual page 381

5
c. Crab Steering Mode
When the steer select switch (5) is in the crab
steer (center) position (6), the front wheels (7)
will steer in the direction the steering wheel is
MT3890
turned and the rear wheels (8) will steer in the
same direction.
1. Crab Steering Left Turn (See page 9.64)
With the steer select switch (5) in the crab steer (center)
position (6), one of the steer select valve solenoids is en-
ergized. The power steering control valve is shifted so
that system pressure from the accumulator charge valve
is applied through the intake side of the power steering
unit metering section.
A specific amount of hydraulic oil is exhausted from the
metering section and routed back to the power steering
control valve, internal to the power steering unit, where it
is channeled through the steer select valve to the right rod
end of the rear steering cylinder.
Oil from the left rod end of the rear steering cylinder flows
through the steer select valve to the left rod end of the
front steering cylinder. Oil from the right rod end of the
front steering cylinder flows to the power steering control
valve, then to the return filter in the reservoir.
Model MMV Rev. 12/04
7
6
5
8
2. Crab Steering Right Turn (See page 9.66)
With the steer select switch (5) in the crab steer (center)
position (6), one of the steer select valve solenoids is en-
ergized. The power steering control valve is shifted so
that system pressure from the accumulator charge valve
is applied through the intake side of the power steering
unit metering section.
A specific amount of hydraulic oil is exhausted from the
metering section and routed back to the power steering
control valve, internal to the power steering unit, where it
is channeled to the right rod end of the front steering
cylinder.
Oil from the left rod end of the front steering cylinder flows
through the steer select valve to the left rod end of the
rear steering cylinder. Oil from the right rod end of the
rear steering cylinder flows through the steer select valve
to the power steering control valve, then to the return filter
in the reservoir.
Hydraulic System
MM1820
9.83