Oscillating Axle System; Oscillating Axle Lockout Test - JLG 400S Service And Maintenance Manual

3.6 OSCILLATING AXLE SYSTEM

The oscillating front axle is attached to the frame by a pivot
pin, which allows all four wheels to remain on the ground
when traveling on rough terrain. There are two lockout cylin-
ders connected between the frame and the axle. The lockout
cylinders allow the axle to oscillate when the boom is in Trans-
port Position.
The lockout cylinders will hold down the oscillating axle so to
prevent its further movement if:
• Main boom rises above elevation by more than 5°; OR
• Fly boom telescopes out 12 in. (305 mm) or more.
If the boom is telescoped less than 12 in. (305 mm) and boom
is no more than 5° greater than horizontal (with respect to the
turntable), the turntable can swing 360° continuously without
locking up the oscillating axle for better traction.
The boom angle is monitored by the JLG Control System
through an angle sensor; the fly boom telescope is monitored
by two proximity switches mounted on the main boom side.
When the JLG Control System senses the conditions are met, it
sends a signal to the 2-speed/lock up valve to supply pressure
to lock up the cylinders.
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SECTION 3 - CHASSIS & TURNTABLE

3.7 OSCILLATING AXLE LOCKOUT TEST

LOCKOUT SYSTEM TEST MUST BE PERFORMED QUARTERLY, ANY TIME A SYS-
TEM COMPONENT IS REPLACED, OR WHEN IMPROPER SYSTEM OPERATION IS
SUSPECTED.
NOTE: Ensure boom is fully retracted, lowered, and centered
between rear wheels prior to beginning lockout cylinder
test.
1. Place a 6 in. (15.2 cm) high block with ascension ramp in
front of left front wheel.
2. From platform control console, start engine.
3. Place the Drive control lever to the forward position and
carefully drive machine up ascension ramp until left
front wheel is on top of block.
4. Carefully activate Telescope or Main Boom Lift control
and take the boom out of the transport position.
5. Place Drive control lever to Reverse and drive machine
off of block and ramp.
6. Have an assistant check to see that left front or right rear
wheel remains elevated in position off of ground.
7. Return boom to stowed position. When boom reaches
center, stowed position, lockout cylinders should release
and allow wheel to rest on ground, it may be necessary
to activate Drive to release cylinders.
8. Place the 6 in. (15.2 cm) high block with ascension ramp
in front of right front wheel.
9. Place Drive control lever to Forward and carefully drive
machine up ascension ramp until right front wheel is on
top of block.
10. Repeat steps 4 through 7 to check the opposite side of
the oscillating axle.
11. If lockout cylinders do not function properly, have quali-
fied personnel correct the malfunction prior to any fur-
ther operation.
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