JLG 20VP (3120728) Service Manual - Manual (Page 29)

SECTION 2 - SERVICE PROCEDURES
3120728 – JLG Lift – 2-11
NOTE: The gear oil can be drained out when the side cover
is removed in the next step. Remove the side cover
from the gear box with the drive shaft side pointing
down, then tilt drive motor/gear box assembly to
drain the oil into a suitable container.
2. Remove the four (4) hex cap screws securing the
side cover to the gear box housing, and remove the
side cover and rubber seal ring. (Note: Early model
machines did not have the rubber seal ring and were
sealed with sealant only.) Be careful not to scratch or
gouge the mating surfaces between the cover and
the gear box housing. This area is sealed by the rub-
ber ring/sealant and may leak oil if damaged.
3. Remove the wave washers from atop the large and
small bearings and lay inside their respective holes
in the side cover.
4. Using a suitable catch container, drain the gear oil
from the gear box housing.
5. Remove the drive shaft assembly from the housing.
Place the drive motor/gear box assembly on a
hydraulic press with the open side of the gear box
housing facing down. Support the gear box housing
surface but do not block the free travel of the drive
gear and bearings, on the drive shaft or the pinion
gear assembly.
6. With the open surface of the housing properly sup-
ported, carefully press the drive shaft down through
until it is free of the housing. When the drive shaft
assembly is free, slide it completely out of the hous-
ing.
7. To remove the large (47mm) (cover side) bearing
and (housing side) bearing from the drive shaft, use
a suitable hydraulic press and press the bearing(s)
off the shaft. Keep the spacer from between the
cover side bearing and the drive shaft gear for reuse
during assembly.
8. To remove the small (32mm) bearing(s) from the
gear (brass) and pinion assembly, use a suitable
hydrauic press and press the bearing(s) off the gear
and pinion shaft.
9. To remove the (brass) worm gear from the pinion
assembly, use a suitable hydraulic press and press
the gear off the pinion shaft. Keep the (brass) gear
key for reuse during assembly.
10. Inspect the drive shaft seal for cuts, cracks and
wear, or if showing signs of leakage. Replace if nec-
essary.
Gear/Pinion Shaft Assembly (See Figure 2-9.)
1. Locate the pinion gear/shaft, place the key for the
(brass) worm gear into the slot on the gear shaft.
2. Press the (brass) worm gear onto the pinion shaft
and align the keyway in the (brass) worm gear with
the key on the pinion shaft. Press the (brass) worm
gear onto the shaft until it bottoms out against the
pinion gear teeth.
NOTE: Press bearings onto the shaft pressing only against
the bearing inner race. Do not press against the
outer race or damage could occur to the bearing.
3. Press the small (32mm) bearings onto the ends of
the pinion shaft. The inner race of the bearing on the
pinion gear side can be bottomed out against the
pinion gear. Do not press the bearing on the (brass)
worm gear side of the shaft in tight against the
(brass) worm gear. This bearing must be flush with
the end of the shaft on the outside, yet have clear-
ance from the (brass) worm gear on the inside, so it
can rotate freely.
Drive Shaft Assembly (See Figure 2-10.)
1. Slide the (housing side), 42mm x 25mm x 12mm
(thinner) bearing onto the long end of the drive shaft.
Press the bearing inner race until it bottoms against
the shaft shoulder between the drive gear and the
bearing.
2. Slide the narrow spacer onto the drive gear end of
the shaft and press the (cover side) 42mm x 20mm x
14mm (wider) bearing onto the drive shaft until it
bottoms against the spacer. This bearing should be
flush with the end of the drive shaft.
Figure 2-9. Gear/Pinion Shaft Assembly.
SIDE PROFILE
32mm
BEARING
PINION GEAR/
SHAFT
WORM GEAR
KEY
WORM
GEAR
(BRASS)
32mm
BEARING
LEAVE
GAP HERE