Spicer Single Drive Axles Service Manual: 34DS, 34RS, 38DS, 38RS, DS340, RS340, DS380, RS380, DS400, RS400, DS3 - Manual (Page 35)

Adjustments
32
Ser
vice Procedure
Ring Gear and Pinion Tooth Contact
Note: Rear axle gearing is shown in the following instructions. Correct tooth contact patterns and adjustments are the same for
forward and rear axles.
Check Tooth Contact Pattern (NEW GEAR)
Paint twelve ring gear teeth with marking compound and roll the gear to obtain a contact pattern. The correct pattern is well-cen-
tered on the ring gear tooth with lengthwise contact clear of the toe. The length of the pattern in an unloaded condition is approx-
imately one-half to two-thirds of the ring gear tooth in most models and ratios.
Check Tooth Contact Pattern (USED GEAR)
Used gearing will not usually display the square, even contact pattern found in new gear sets. The gear will normally have a “pock-
et” at the toe-end of the gear tooth which tails into a contact line along the root of 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 pattern is clear of 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 variable and is considered acceptable as long as it does not run off the
tooth at any point.
Face
width
Toe
Root
Top land
Heel
Tooth
depth
Could vary in length.
Pattern should cover
1/2 tooth or more
(face width).
Pattern should be
evenly centered
between tooth
top land and root.
Pattern should be clear of tooth toe.
Correct Pattern New Gearing
Pocket may be
extended.
Pattern along
the face width
could be longer.
Correct Pattern Used Gearing