Pull the third member and clean all the gear oil off of the ring and pinion, then measure the backlash in 4 places and write it down, Take the ring gear off of the open carrier and set the posi carrier in a cold place, set the ring gear on or near a stove so you can warm it up to 130 F to 200 F, be careful on handling it when hot
Then slide the ring gear on the posi and get several ring gear bolts started and tighten, remember the ring gear bolts on 8 3/4 are all left hand threads
, not standard right hand threads
Once you get the ring gear mounted and torque all the bolts to 55 Ft lbs. set the carrier into the third member and adjust the adjusters so you get zero end play on the carrier bearings left to right
. Once that is done move the carrier over to the passenger side by adjusting (tightening) and loosening the two adjusters until you get between .0015 to .0010 back lash, check the backlash in all four places again to make sure the ring gear run out does not exceed .002 runout
If the ring gear run out exceeds .002 take it off the carrier amd move it 80 to 120 degrees on the carrier and check it again
Once you get the ring gear run out where you want it with no carrier bearing preload, .0010 to .0015 backlash, then tighten the passenger side adjuster until you get the original back lash you had, + or- .0010
IHThs
If you don't have a tool to use on the adjusters go buy one first, it will take a lot of preload on the passenger side adjuster to make the correct backlash come back, it might be okay to loosen the left adjuster between 1/8 to maybe 1/3 third of a turn on the left adjuster to get the backlash set properly, do that as a last resort though, crank on the passenger side adjuster as hard as you can first
IHTHs, it really helps to have a factory service manual also