Originally Posted By: MolaKule
... This specialized component can be calcium- or magnesium-based and is used in MODERN, DEDICATED, finished Manual Transmission (MTF) lubricants.
Understood. How long has that "MTF" been common in mundane cars? Just in time to see manuals become an endangered species...
In 1998, at about 360k miles, my Mazda had its most expensive mechanical repair, one of only two I didn't perform myself. That was replacing bearings in its transmission. Shortly after getting it back from the shop, I noticed it was burping oil out the vent in the top of the transmission housing, even though it was not overfilled. The oil was obviously not what Mazda specified (Type F), because it was higher viscosity and not pink. I called the shop to ask what it was. The guy said it was synthetic oil for transmissions, and "better" than Type F, therefore he would not change it. They couldn't (or wouldn't ) tell me specifically what brand and model oil it was.
The transmission continued spitting the new thick oil out the vent, until it was dangerously low. I added ATF, repeatedly. Getting that stopped wasn't easy, but I finally succeeded. I never knew whether the oil loss was caused by the change in oil type, or by some mistake they made reassembling the transmission. The transmission went another ~240k with no further problems except being harder to shift into 2nd gear when cold than it had been before the repair. It was quieter than when new.