Spicer Ring and Pinion Tooth Contact Pattern User Manual

Pattern should range from just clear of the toe end to about

pattern observed before disassembly. A correct pattern is up

Spicer

Drive Axles

P/N: SHAIS168B

Ring and Pinion Tooth Contact Pattern Information

Affected Models: All Dana Drive Axle Models

Dana drive axles require adjustment of the ring gear and pinion tooth contact at overhaul or anytime the axle has been
disassembled. Most axles require the same distinctive pattern, described in our service publications.

After differential preload and gear backlash adjustments are complete, check the tooth contact pattern and adjust if
necessary. Tooth contact patterns are a function of the relative positions of the ring gear and the pinion. An improper
pattern will require a relocation of either or both. Always adjust pinion position first, if necessary, then the ring gear
position. Always check backlash when done.

New Gearing

Paint ring gear with marking compound and roll the gear to
obtain a contact pattern as shown in the photograph. The
length of the pattern in a unloaded condition is
approximately one-half to two-thirds of the ring gear tooth
in most models and ratios.

3/8” off the toe end. The pattern should be evenly centered
between tooth top land and root.

Used Gearing

Used gearing may not display the round, even contact
pattern found in new gear sets. The gear may have a
“pocket” at the heel end of pattern. The more “use” a gear
has had, the more dominate characteristic of the pattern.

Adjust used gearing so as to display the same contact

slightly off the toe and centers evenly along the face width
between the top land and the root. Otherwise, the length
and shape of the pattern are highly variable and are
considered acceptable as long as there is some pattern on
toe end of the tooth.

New Gearing

Used Gearing

®

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SHAIS168B – Ring and Pinion Contact Pattern Information

Remove Shim

Add Shim

Decrease Backlash

Increase backlash

Decrease Backlash

then the backlash.

If necessary, adjust the contact pattern by moving the ring gear or drive pinion. Ring gear position
controls the backlash. This adjustment moves the pattern along the face width or up and down the
gear tooth. Pinion position is determined by the size of the shims behind the pinion bearing cage,
and controls tooth depth contact.

These adjustments are interrelated. As a result, they must be considered together even though
the pattern is altered by two distinct operations. When making adjustments, first adjust the pinion,

If the contact pattern shows incorrect tooth depth contact, change drive pinion position by altering the shim
pack. Used gearing should achieve proper contact with the same shims removed form the axle at disassembly.
Always recheck backlash after shim changes.

Loosen the opposite adjuster one notch. Return to adjuster on the tooth side of the ring gear and tighten adjuster
until it contacts the bearing cup. Continue tightening the same adjuster 2 or 3 notches. Recheck backlash.

Tighten the opposite adjuster one notch. Return the adjuster on the tooth side of the gear and tighten adjuster
until it contacts the bearing cup. Continue tightening the same adjuster 2 to 3 notches. Recheck backlash.

Incorrect Pattern - Adjust Pinion Position

Pattern to close to
tooth top land and
off center.

Pattern to close to
tooth root.

Incorrect Pattern - Adjust Backlash

Pattern is more
than 3/8” off the
toe of tooth.

Pattern is running
off the toe of the
tooth.

by loosening the bearing adjuster on the tooth side of the ring gear several notches.

by loosening the bearing adjuster on the tooth side of the ring gear several notches.

Increase Backlash

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