JLG 26MRT Service Manual - Manual (Page 34)

SECTION 2 - PROCEDURES
2-22 – JLG Sizzor – 3120892
Ring Gear and Pinion Tooth Pattern
Interpretation
The TOE of the gear tooth is the portion of the tooth sur-
face at the end towards the center. The HEEL of the gear
tooth is the surface of the top of the tooth. Every gear has
a characteristic pattern. The illustrations in Figure 2-18
show typical patterns only, and explain how patterns shift
as gear location is changed. When making pinion position
changes, shims should be changed in the range of 0.051
mm (0.002 in) to 0.102 mm (0.004 in) until the correct pat-
tern has been obtained.
When a change in backlash is required, backlash shims
should be changed in the range of 1-1/2 times the amount
of backlash required to bring the gears into specification.
For example, if the backlash needs to be changed by
0.102 mm (0.004 in), the shim pack should be changed by
0.152 mm (0.006 in) as a starting point. The actual amount
of backlash change obtained will vary depending upon
the ratio and gear size.
High backlash is corrected by moving the ring gear closer
to the pinion. Low backlash is corrected by moving the
ring gear away from the pinion. These corrections are
made by switching shims from one side of the differential
case to the other.
NOTE: When making changes, note that two variables are
involved. Example: If you have the backlash set cor-
rectly to specifications and you change the pinion
position shim, you may have to readjust the back-
lash to correct specification before checking the pat-
tern.
GEAR TEETH MAY HAVE SHARP EDGES. WHEN HANDLING
GEARS, USE CAUTION TO AVOID PERSONAL INJURY.
Figure 2-18. Ring Gear and Pinion Tooth
Contact Pattern