Ring gear backlash adjustment

WARNING: This page is about a different car, the 2005 Mazda RX-8. However, it is still accessible from the selected car via links, so may be relevant.

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
1. 158.8-159 mm {6.252-6.267 in}
Fig 1: Measuring Side Bearing Race And Differential Gear Case Component Height
Courtesy of MAZDA MOTORS CORP.
Measure the width of the section of the differential gear case component installed in the differential carrier. This is value B.
Standard width B
1. 171 mm {6.73 in}
Fig 2: Measuring Width Of Section Of Differential Gear Case Component
Courtesy of MAZDA MOTORS CORP.

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})
If the combined thickness of the previously assembled adjustment shims is equal to the calculated thickness, use the shims as they are.

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 table below.

ADJUSTMENT SHIM THICKNESS SPECIFICATIONS

Identification mark	Thickness (mm {in})	Identification mark	Thickness (mm {in})
550	5.50 {0.217}	605	6.05 {0.238}
560	5.60 {0.220}	610	6.10 {0.240}
565	5.65 {0.222}	615	6.15 {0.242}
570	5.70 {0.224}	620	6.20 {0.244}
575	5.75 {0.226}	625	6.25 {0.246}
580	5.80 {0.228}	630	6.30 {0.248}
585	5.85 {0.230}	635	6.35 {0.250}
590	5.90 {0.232}	640	6.40 {0.252}
595	5.95 {0.234}	650	6.50 {0.256}
600	6.00 {0.236}	-	-

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.

Assemble the differential gear case component and the side bearing race to the differential carrier.
Tap the selected adjustment shim between the differential carrier and the side bearing race with a plastic hammer as shown in the figure.
Align the bearing cap alignment marks, assemble the bearing cap, and then temporarily tighten the bolts.

Fig 3: Installing Selected Adjustment Shim Between Differential Carrier And Side Bearing Race
Courtesy of MAZDA MOTORS CORP.
Install the dial gauge with the measuring probe of the dial gauge attached perpendicularly to the end of one of the ring gear teeth.

Fig 4: Installing Dial Gauge With Measuring Probe Of Dial Gauge
Courtesy of MAZDA MOTORS CORP.
Secure the drive pinion and measure the backlash of the ring gear.
Backlash
1. Standard:0.09-0.11 mm {0.0035-0.0043 in}
2. Minimum value:0.05 mm {0.0020 in} or more
3. Variance:0.07 mm {0.0028 in} or less
Fig 5: Measuring 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
If the backlash is not within the specification, adjust the gear case component by moving it in the axial direction.
NOTE:
- When moving the gear case component in the axial direction, replace the adjustment shims. If the adjustment shim on the right side is replaced with one that is 0.05 mm {0.0020 in} thicker, replace the one on the left with one that is 0.05 mm {0.0020 in} thinner.