How to adjust 8-3/4" axle bearing preload?

You have to turn the adjuster in or CW, this in turn pushes on the axle/race which pushes against the axle thrust button inside he carrier (hopefully your carrier still has these ) you will know if they are there or not because by turning the adjuster in it will remove any end play or in and out motion of both axles. If every thing works as I stated above what you want to do is remove allend play then back the adjuster out one or two notches. As you will notice these are tappered axle bearings, the adjuster places the race against the tapered rollers, ideally you want as little play as possible without overtightening them. Drive the car 5-10 miles then jack it up to check the end play again, make sure there is very little in and out motion. If you take the time to do it right you will have many miles of trouble free driving. Also you are aware that you need to pack your bearings in grease? They do not lubricate from the rearend fluid. IE: the inner axle seals. I hope this helps you.