Pinion Ring Gear Variation Number: Notes

WARNING: This page is about a different car, the 2005 Ford RV Cutaway, 2005 Ford Econoline, 2005 Ford E450 Super Duty, and 2005 Ford Cutaway. However, it is still accessible from the selected car via links, so may be relevant.

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. For additional information, refer to DRIVELINE SYSTEM-GENERAL INFORMATION .

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 60/70 axles, shimming behind the inner pinion bearing controls this dimension.
  
  Fig 1: Identifying Pinion Ring Gear Variation Number
  Courtesy of FORD MOTOR CO.
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.
- 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 0.010 in). Measure each shim separately with a micrometer.
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 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 in) 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 in) from the drive pinion position shim selected for installation. A pinion etched m-8 (-3), requires 0.08 mm (0.003 in) more shimming than a pinion etched "0". In this instance, add 0.08 mm (0.003 in) to the drive pinion position shim selected for installation to decrease the pinion mounting distance by the amount etched in the pinion.