I don't know how this happened, but the housing truly is partially melted
(this is on my 2wd w/plastic housing, not the metal as on the syncro) it
melted at the mating surface to the engine where the o-ring is.  Engine
started right back up today after replacing all the parts and filling with
fresh water and coolant system flush.  Seems to be fine, I will report more
after replacing the thermo-switch and proper coolant.
Loretta