^^^^ This or a bracket bolted to the top 2 flange bolt holes and mount it in a vise.
Next is a dial indicator.Take the indicator reading before disassembly. Usually .008 backlash minimum.
You will find that a sure grip and the open take different side bearings.
There are many different ways to get side bearing preload. One is to adjust the side bearings to zero backlash,Then tighten the side bearing to push the ring gear away from the pinion achieving desired backlash..
A Factory service manual is your best friend.
