Birdword,
One thing that I have been told in the past is to always use a new nut when putting things back together. You should be able to pick one up at a local pontiac dealer. If you dont use a new one I would at least use a little blue loc-tite to make sure it dont back off in the future. Also, when tightening back down dont over tighten (you dont want it to loose either), theres a certain preload that needs to be set on these bearings. Normally this preload is checked with a in. lb. torque wrench. Most sevice manuals will spell out the procedure to set the preload. If you want some good info do a search in team chevelle or team camaro for a guy that goes by big gear head. He's a nice guy and is willing to help, he knows a lot about rear ends, on cars anyway Nick