Gradall 534B (9020-7317) Service Manual - Manual (Page 44)

The rear driving axle includes planetary hubs which
are powered by hydraulic motors mounted on the
inner face of the hubs. Hydraulic flow to drive
motors is provided only in first and second gear
speed ranges. Drive motors are free-floating in third
gear.
To Disengage Rear Driving Hubs:
To Engage Rear Driving Hubs: Repeat procedure.
NOTE: If machine is moved with keeper pin plate
removed, input shaft pin will pop out.
On/Off/Reset Button (rear drive circuit
breaker)
(on/off switch function on early units
only)
Hydraulic flow to rear axle drive motors is
controlled electrically. A circuit breaker is included
to prevent damage from overload.
If circuit
breaker trips (opens) rear axle drive will be
inoperative.
Rear axle drive can be restored by
depressing and releasing on/off/reset button.
The on/off/reset button also functions as an on/off
switch for rear axle drive on early units.
To determine whether switch is on or off or circuit
breaker has tripped, attempt to move machine using
inching travel. If machine does not respond to
inching travel pedal, switch is off or circuit breaker
is open.
Inching Travel
Inching travel is provided to permit very slow travel
while maintaining high engine speed for other
functions. Because inching travel depends on
hydraulic flow to rear axle drive motors, inching
Continuous driving for two miles or more
in third gear, with rear driving hubs
engaged, can damage hydraulic drive
motors.
travel functions only in first and second gears. There
is no hydraulic flow to drive motors in third gear.
Inching travel is controlled by the service
brake/inching travel pedal. This pedal has three
separate functions:
As illustrated, the three functions occur in sequence
as pedal is depressed from top to bottom of stroke.
To Engage Inching Travel:
OR
Apply parking brake and remove key from
ignition switch.
Remove thumb screws from keeper pin plate.
Remove and rotate plate per photo on pg. 6 (cup
out-engaged-cup in-disengaged).
Secure plate using thumb screws.
Repeat procedure for other hub.
1.
2.
3.
4.
5.
It disconnects front drive axle from
transmission.
It controls hydraulic flow to rear axle drive
motors (hydraulic flow equals speed).
It applies service brake.
1.
2.
3.
Depress service brake/inching travel pedal
approximately 1-1/2 inches to disengage front
driving axle from transmission. At this point rear
drive motors are receiving full flow and travel
speed will not have changed.
Continue to depress pedal to reduce speed-the
more pedal travel, the less speed.
To stop, depress pedal fully.
1.
2.
3.
To resume normal travel, release accelerator
pedal and then, with engine at idle, release ser-
vice brake/inching travel pedal. Depress
accelerator pedal to attain appropriate speed.
Practice inching/braking in a safe open
area until you are thoroughly familiar with
response of machine to pedal travel.
1 2
Rear Driving Axle