Welcome jamesbeat!
One thing I'd like to mention is that at some point someone somewhere, possibly on a forum like this probably came along and said "pffft! SM oil?!? I use this bike chain oil on my sewing machines..." and people there probably also thought it was a crazy idea.
I guess what I'm saying is that we never know where the next "step" in our sewing machine lubrication evolution is going to come from.
I probably wouldn't use Transmission fluid for my machines because I hate the smell of it and what it does to my hair.
I spilled a whole bottle of it in my hair and down my shirt when I changed the transmission in my old firebird. The hose popped out of the tranny and the whole bottle landed on me. No amount of washing with soap, shampoo or even that gritty Fast Orange took it all out. I looked like I was wearing a greasy Tina Turner for a week, just in time for a Christmas party too. Since then, I can't stand the smell of transmission oil.