55 years of setting up rear end gears has taught me one basic fact. When dealing with gears with an established wear pattern:

DO
NOT
MESS
WITH
BACKLASH!

You will create a howl that would make a banshee blush with shame! It's far better to have quiet-running gears and a little more backlash than specified, than to try to create a new running relationship between the ring and pinion gears.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!