Adjustment Shim Assembly Note

Ring gear backlash adjustment 

1. Stack the side bearing race and differential gear case component on the surface plate as shown in the figure, and measure the height using a caliper and a ruler. This is value A.

   Standard Height A 

   158.8-159 mm (6.252-6.267 in) 

   Fig 1: Ring Gear Backlash Adjustment

   Courtesy of MAZDA MOTORS CORP.
2. Measure the width of the section of the differential gear case component installed in the differential carrier. This is value B.
Fig 2: Measuring Width Of Section Of Differential Gear Case
Courtesy of MAZDA MOTORS CORP.

Standard width B 

171 mm (6.73 in) 

1. The combined thickness of the left and right adjustment shims is obtained by the following formula.

   Shim thickness (mm (in)) = B-A+ (0.01-0.03 (0.0004-0.0118 in)) 

   Fig 3: Shim Thickness

   Courtesy of MAZDA MOTORS CORP.
2. If the combined thickness of the previously assembled adjustment shims is equal to the calculated thickness, use the shims as they are.
3. If the combined thickness of the previously assembled adjustment shims is not equal to the calculated thickness, or if the adjustment shims have to be replaced, select two appropriate adjustment shims from the adjustment shims specifications.
   Fig 4: Installing Adjustment Shims

   Courtesy of MAZDA MOTORS CORP.
   NOTE:

   • If the adjustment shims are to be reused, assemble the left and right shims that were identified during disassembly.
   • When assembling the side bearing races, do not mix the left and right side bearings that were identified during disassembly.
4. Assemble the differential gear case component and the side bearing race to the differential carrier.
5. Tap the selected adjustment shim between the differential carrier and the side bearing race with a plastic hammer as shown in the figure.
6. Align the bearing cap alignment marks, assemble the bearing cap, and then temporarily tighten the bolts.
7. Install the dial gauge with the measuring probe of the dial gauge attached perpendicularly to the end of one of the ring gear teeth.
8. Secure the drive pinion and measure the backlash of the ring gear.

   Backlash 

   Standard : 0.09-0.11 mm (0.0035-0.0043 in) 

   Minimum value : 0.05 mm (0.0020 in) or more 

   Variance : 0.07 mm (0.0028 in) or less 

   Fig 5: Checking Ring Gear Backlash

   Courtesy of MAZDA MOTORS CORP.
   NOTE:

   • Measure the backlash at 4 locations around the ring gear. Make sure all of the 4 locations are within specification, and the minimum value for the 4 locations is 0.05 mm (0.0020in) or more  and the variance is 0.07 mm (0.0028 in) or less 
9. If the backlash is not within the specification, adjust the gear case component by moving it in the axial direction.

Fig 6: Measuring Backlash Of Ring Gear Over 4 Different Positions

Courtesy of MAZDA MOTORS CORP.