FYI,
Thanks to some suggestions from the group, I tracked down the cause of my leak. The gasket under the right side rear tail light assembly was the culprit. Turns out the nuts holding the thing on weren't very tight either, but I'm replacing left and right side gaskets as soon as they come in at the dealer.
...and on another note if anybody on the list is interested I'll be putting the car up for sale as soon as that is done. Was made an offer I can't refuse by my dad on his 2002 F150 pickup. Car is red, totally stock GL 4D,
80K mi. Long Island NY area. E-mail me off list at l-u-n-d-q-u-i-s-t-@-i-e-e-e-.-o-r-g (remove the dashes) if interested.