Thanks everybody! Got it off last night. Guess it needed an extra day of soaking in penetrant. Also, a new pair of vise-grips since the teeth on my old one were worn, plus a helper so I could use both hands on the cheater bar I had on the socket wrench. Ended up with busted knuckles on all 4 hands when it finally gave. No puddles of fluid this morning, so I'm happy.

'89 4Runner, V6, Auto, 180K, Some stuff's stock, some isn't.