Mazda RX-8 Workshop Manual page 1530

Locknut Assembly Note
1. Apply differential oil to the thread of a new locknut.
2. Tighten a new locknut with the torque recorded at the drive pinion preload adjustment using the SST.
3. Verify that the drive pinion preload is within the specification.
If not within the specification, perform the preload adjustment again.
Differential drive pinion preload
1.3—1.7 N·m {14—17 kgf·cm, 12—15 in·lbf}
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.