Pinion Ring Gear Variation Number

Note: If so equipped, install a new pinion shaft oil slinger if bent or mutilated.

Note: The differential ring gear and pinion is only available in a matched set. Matching numbers etched on both the differential ring gear and pinion are for verification. If installing a new differential ring gear and pinion, verify these numbers match before proceeding with assembly. The end of the pinion with the etched figures is the "button" end.

Note: Use the gear contact pattern method to verify the final pinion position is valid.





1. Shim the pinion as follows:
- Etched on the button end of each pinion is a zero (0), or a plus (+) or minus (-) with a number. This number indicates the best running position for each particular differential ring gear. On Model 80 axles, shimming behind the inner pinion bearing cup controls this dimension. On Model 60/70 axles, shimming behind the inner pinion bearing controls this dimension.





2. Measure between the centerline of the differential ring gear to the backface of the drive pinion.
- The distance between the centerline of the differential ring gear to the backface of the drive pinion is:
+ 127 mm (5.000 inches) for Model 60 axles.
+ 136.5 mm (5.375 inches) for Model 70 axles.
+ 147.6 mm (5.812 inches) for Model 80 axles.

3. If reusing the old differential ring gear and pinion, proceed as follows:
- On Model 60/70 axles, measure and record the old drive pinion position shim thickness and select a new shim of the same dimension.
- On Model 80 axles, measure and record the old drive pinion position shim pack thickness and build a new pack of shims to this same dimension.
- To change the pinion adjustment, drive pinion position shims are available in the thickness of 0.08, 0.13, and 0.25 mm (0.003, 0.005, and 0.0 10 inch). Measure each shim separately with a micrometer.

4. If installing a new differential ring gear and pinion, notice the (+) or (-) etching on both the old and new pinion, and adjust the new shim (shim pack for Model 80 axles) thickness to compensate for the difference of these two figures. If so equipped, include the oil slinger thickness in the total measurement to correctly set pinion depth.
- For example, a pinion etched with m+8 (+3) requires 0.08 mm (0.003 inch) less shimming than a pinion etched " 0 ". This means to increase the mounting distance by the amount etched in the pinion, subtract 0.08 mm (0.003 inch) from the drive pinion position shim (shim pack for Model 80 axles) selected for installation. A pinion etched m-8 (-3), requires 0.08 mm (0.003 inch) more shimming than a pinion etched "0". In this instance, add 0.08 mm (0.003 inch) to the drive pinion position shim (shim pack for Model 80 axles) selected for installation to decrease the pinion mounting distance by the amount etched in the pinion.





New Pinion Conversion Chart (Metric)