JLG 80SL Service Manual - Manual (Page 38)

SECTION 3 - CHASSIS, PLATFORM & SCISSOR ARMS
3-2 – JLG Lift – 3121325
Drive Hub
DRIVE HUB UNITS SHOULD ALWAYS BE ROLL AND LEAK
TESTED BEFORE DISASSEMBLY AND AFTER ASSEMBLY TO
MAKE SURE THAT THE UNIT’S GEARS AND SEALANTS ARE
WORKING PROPERLY.
The following information briefly outlines what to look for
when performing these tests.
IF THE MACHINE IS ON ANY INCLINE, THE WHEELS MUST BE
ADEQUATELY BLOCKED PRIOR TO MANUALLY DISENGAGING
THE BRAKES. FAILURE TO DO SO MAY RESULT IN INJURY OR
EVEN DEATH.
Roll Test
The purpose of the roll test is to determine if the unit's
gears are rotating freely and properly. You should be able
to rotate the wheel or hub of the gearbox by hand. If you
feel more drag in the gears only at certain points, then the
gears are not rolling freely and should be examined for
improper installation or defects. Some gear packages roll
with more difficulty than others. Do not be concerned if the
gears in your unit seem to roll hard as long as they roll
with consistency.
Leak Test
The purpose of a leak test is to make sure the unit is air
tight. You can tell if your unit has a leak if the pressure
gauge reading on your leak checking fitting starts to fall
after the unit has been pressurized and allowed to equal-
ize. Leaks will most likely occur at the pipe plugs, the main
seal or wherever o-rings are located. The exact location of
a leak can usually be detected by brushing a soap and
water solution around the main seal and where the o-rings
or gaskets meet on the exterior of the unit, then checking
for air bubbles. If a leak is detected in a seal, o-ring or gas-
ket, the part must be replaced, and the unit rechecked.
Leak test at 10 psi for 20 minutes.
NOTE: Due to the small air volume inside this Torque-Hub, it
will pressurize to 10 psi very quickly. If the pressure
becomes excessive in the unit the seals will be
destroyed.
Lubricant
The torque hub unit is shipped with 90W gear oil. It is
designed to utilize the same oil throughout its service life.
However, should it need to be serviced the oil will need to
be drained and replaced.
In the event of servicing, fill the unit with Arco H.D. 120#
Drum or Exxon GX 80W-90.
Hub Disengaging and Oil Checking Procedure:
1. Loosen the two Screws (2) securing the Circlip (3).
2. Slide the Circlip (3) in the direction of the arrow.
3. Remove the Pin (4).
4. The proper gear oil level should be to the base of the
opening. Add gear oil if needed.
5. Turn the Pin (4) around and place back onto Hub
(1).
NOTE: Side of Pin that was facing outside should now be
facing the inside of the hub.
6. Slide Circlip (3) in opposite direction of arrow to
secure the Pin. Tighten Screws (2) to secure the Cir-
clip in place.
1
2
3
4
Figure 3-1. Torque Hub
1. Drive Hub
2. Screw
3. Circlip
4. Pin