Purchase your Ring and Pinion Kit @ drivetrain.com and recevie
free telephone technical suppor if required during setup!
Ring gear
and pinion tooth pattern interpretation
When setting the pinion position, many of the service manuals
required a final pinion position check by using gauges that verified the dimension
from the center line of the differential carrier (center line of ring gear) to the
face of the pinion (button). This surface (button) is not used on all new gears for
verifying the pinion position. The service tools will be used to establish the proper
amount of shims required prior to installing the pinion gear. The final pinion position
will be verified by using the GEAR CONTACT PATTERN METHOD, as described in this bulletin.
RING GEAR AND PINION TOOTH CONTACT PATTERN
The TOE of the gear tooth is the portion of the tooth surface
at the end towards the center. The HEEL of the gear tooth is the portion of the tooth
surface at the outer end. The TOP LAND of a gear tooth is the surface of the top
of the tooth. Every gear has a characteristic pattern. The illustrations show typical
patterns only, and explains how patterns shift as gear location is changed. When
making pinion position changes, shims should be changed in the range of .002 inch
(.05 mm) to .004 inch (.10 mm) until correct pattern has been obtained.
When a change is 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 needed to be changed by .004
inch (.10 mm), the shim pack should be changed by .006 inch (.15mm) 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 correctly to specifications and you change
the pinion position shim, you may have to readjust the backlash to the correct specification
before checking the pattern. Refer to pattern interpretation.
WARNING: Gear teeth may have sharp edges. When handling
gears, use care to avoid personal injury.
STEPS:
(1) Paint ring gear teeth with a marking compound to both
the drive and coast side.
(2) Rotate ring gear one complete revolution in both directions
while load is being applied with a large screwdriver or simular tool between the
carrier casting and differential case flange.
PATTERN MOVEMENTS SUMMARIZED
(1) Decreasing backlash moves the ring gear closer to the
pinion.
Drive pattern (convex side of gear) moves slightly
lower and toward the toe.
Coast pattern (concave side of gear) moves lower
and toward the toe.
(2) Increasing backlash moves the ring gear away from the
pinion.
Drive pattern moves slightly higher and toward the
heel.
Coast pattern moves higher and towards the heel.
(3) Thicker pinion position shim with the backlash constant
moves the pinion closer to the ring gear.
Drive pattern moves deeper on the tooth (flank contact)
and slightly toward the toe.
Coast pattern moves deeper on the tooth and toward
the heel.
(4) Thinner pinion position shim with the backlash constant
moves the pinion further from the ring gear.
Drive pattern moves toward the top of the tooth (face
contact) and toward the heel.
Coast pattern moves toward the top of the tooth and
slightly toward the toe.
| Old Pinion Marking |
New Pinion Marking (Metric)
|
|
-10
|
-8
|
-5
|
-3
|
0
|
+3
|
+5
|
+8
|
+10
|
|
+10
|
+.20
|
+.18
|
+.15
|
+.13
|
+.10
|
+.08
|
+.05
|
+.03
|
0
|
|
+8
|
+.18
|
+.15
|
+.13
|
+.10
|
+.08
|
+.05
|
+.03
|
0
|
-0.3
|
|
+5
|
+.15
|
+.13
|
+.10
|
+.08
|
+.05
|
+.03
|
0
|
-.03
|
-.05
|
|
+3
|
+.13
|
+.10
|
+.08
|
+.05
|
+.03
|
0
|
-.03
|
-.05
|
-.08
|
|
0
|
+.10
|
+.08
|
+.05
|
+.03
|
0
|
-.03
|
-.05
|
-.08
|
-.10
|
|
-3
|
+.08
|
+.05
|
+.03
|
0
|
-.03
|
-.05
|
-.08
|
-.10
|
-.13
|
|
-5
|
+.05
|
+.03
|
0
|
-.03
|
-.05
|
-.08
|
-.10
|
-.13
|
-.15
|
|
-8
|
+.03
|
0
|
-.03
|
-.05
|
-.08
|
-.10
|
-.13
|
-.15
|
-.18
|
|
-10
|
0
|
-.03
|
-.05
|
-.08
|
-.10
|
-.13
|
-.15
|
-.18
|
-0.20
|
Rear End & Differential Ring Gear and Pinion Sets 
