[joeydurango]

Yes, backing plate contact areas looked similar and normal, and yes, I greased them.

Cleaned and greased the anchor posts - no wear.

Yes, compared sides for wear patterns and axle play - no appreciable differences. No excessive play in the axle that I could tell.

Diff had good oil in it and has been full (I check periodically); at the same time as this brake job I did replace the gasket and refill with fresh gear oil (old gasket was beginning to seep). However the noise began months before gasket replacement and there's no change with fresh oil.