As I said in the post, the lash was actually tighter and I backed the ring gear off a little. That improved the pattern. It moved the pattern back, closer to the middle of the gear. Especially on the drive side.
As I try to at least reduce the rear noise going down the road, I am also trying to understand the cause and effect of changes. So, since I pulled the ring gear away from the pinion and that improved the pattern by moving it back away from the toe and more into the middle, will moving the pinion away from the ring gear (as suggested) do the same thing while allowing me to move the ring gear back closer to the pinion giving it a tighter lash, as suggested?
Thanks for the help!
Moving the pinion fore and aft is not the same as adjusting the lash. Backlash just allows for a tight enough engagement so that there's 1) room for oil and 2) room for thermal expansion. Pinion depth is primary and needs to be right. If the crush sleeve is keeping you from wanting to pull the pinion, it's not a bad time to invest in a crush sleeve eliminator.
The sharp cutoff on the pattern shown looks to be too deep, to me. Most pattern books will show a fading clean spot, without a sharp line like that. Also, you want to make sure you get enough preload on the ring gear when running the pattern, or it won't show well. I usually use a pry bar or something similar to load it up pretty hard.
