Guess what I found out!?
All along, that mysterious noise I was hearing is the a.c. compressor clutch... It makes more noise than it should, which means one of these days it will quit altogether, but I did make it through another ridiculous AZ summer!...
And in better news, yesterday's oil change was first since June, and she was just barely 1/2qt low... seems to be holding up quite well compared to some other stories I've read here.
Also changed the transfer case oil and outfitted her with a pair of new running shoes...
Now........ if I could just get geared up to give her a much needed paint job, things will be all good in VX-land!!