Spicer Single Drive Axles Service Manual: S140 Series - Manual (Page 29)

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Adjust Tooth Contact Pattern
Adjust T
ooth Contact
Pattern
Adjust Ring and Pinion Tooth Contact Pattern
1 - Face width
2 - Tooth depth
3 - Heel
4 - Top land
5 - Root
6 - Toe
1. Identify if new or used gearing.
2. Check tooth contact pattern (new or used gearing).
New Gearing - Correct Pattern
• Paint six ring gear teeth 180° apart and roll the gear
to obtain a contact pattern. The correct pattern is
slightly below center on the ring gear tooth with
lengthwise contact up off the toe. The length of the
pattern in an unloaded condition is approximately
one-half (1/2) to two-thirds
(2/3) of the ring gear tooth in most models and
ratios.
• The pattern could vary in length and should cover
half (1/2) of the tooth or more (face width). The pat-
tern should be evenly centered between tooth top
land and root and should be up off the tooth toe.
Used Gearing - Correct Pattern
• Used gearing will not usually display the square,
even contact pattern found in new gear sets. The
gear will normally have a “pocket” at the heal end of
the gear tooth. The more use a gear has had, the
more the line becomes the dominant characteristic
of the pattern.
• Adjust used gear sets to display the same contact
pattern observed before disassembly. A correct pat-
tern is up off the toe and centers evenly along the
face width between the top land and root. Otherwise,
the length and shape of the pattern are highly vari-
able and is considered acceptable as long as it does
not run off the tooth at any point.
1 - Pattern along the face width could be longer
Adjust Contact Pattern
• If necessary, adjust the contact pattern by changing
the ring gear position.
• Ring gear position controls the backlash. This
adjustment moves the contact pattern along the face
width of the gear tooth.
Note: This is a shimless pinion designed carrier. If the pattern
shows an incorrect pinion cone position, check to make
sure the inner pinion cup is fully seated. Use a feeler
gauge.
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