On today’s show (#200929) a guy “Peter” called in who had transmission fluid disappearing, and crankcase oil increasing.
Back in the 70’s I had a transmission vacuum modulator valve, (which was screwed into the side of my Audi transmission and was connected to a vacuum line,) develop a rupture in its diaphragm, which caused transmission fluid to be sucked from the transmission into the vacuum line and up into the intake manifold. The fluid then entered the cylinders, and not only caused some occasional weird smoke and smell, but got by the rings and entered the crankcase, causing my oil level to rise, and the oil had a brown tint to it. I had the same loss of transmission fluid, but no leak. The slipping transmission was from a bad vacuum modulator valve.
Sounds like this guy may have the same problem. I hope he reads this post!