The squirt of Seafoam Deep Creep seems to have worked for the time being. No squeaks, screeches, or tweets as of yet. New ignition module swapped in a few minutes ago, as well - was barely able to "cheat" this time and just rotate the distributor enough to get to the module screws, rather than pulling the whole assembly out to mess with it.
Feeling MUCH better about my situation knowing that I'm not looking at a $500 differential rebuild (yet).
Feeling MUCH better about my situation knowing that I'm not looking at a $500 differential rebuild (yet).