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

Aaron and I just finished putting his Duster's 8-3/4" rearend back together with new everything. This one came from a '69 Charger, so it has the bearing preload adjuster on the passenger side axle.

I need someone to reply who is very well versed in how this adjuster functions - what it does and how it does it. The axles have way too much end play, so I need to know how to go about making the adjustments.

I believe it is also supposed to have a clip of some sort under one of the retainer flange bolts that keeps the adjuster locked down. If so, it is missing and I need to know what one looks like (any pics appreciated).

Thanks,
Jerry