Welp, thanks for the info guys - here is what happened:
Took the car to a local independent (no recommendations from anyone, just a hunch)...and I explored with the mechanic when he put the car on the lift. This is a weird thing, but the vacuum modulator for tranny popped off. The mounting bracket was intact, the modulator just blew itself straight off. The whitish plastic piston inside the black plastic piece was sheared in half and dropped out of the car as she was being lifted.
So, one new modulator and 4.5 qts of tranny fluid later and ~$98 total later...the ultra-reliable is back to being ultra-reliable and is shifting smoother and crisper than she ever has.
Now, if this only worked for my old 300D...
John J. Meadows
'85 190E 2.3L 105k mi.
'83 300D Turbo 298k mi.