The old Ford auto transmissions used a modulator valve that ran off manifold vacuum. When that diaphram ruptured, you would suck trans fluid into the engine. The fogging was incredible out the exhaust. I literally stopped traffic once in a 1980 Bronco. Everyone thought the truck was on fire. Any hint of trans fluid odor at the tailpipe?
Edit: Oops... didn't see lm6y's reply so I'm a little redundant.
