The Dodge Boys are an endless source of amusement for me. Sometimes they hit on a really neat trick, but mostly the "tricks" are just a waiting disaster in a bus. They arent pushing 12 tons up a grade routinely. Instead they are pulling stumps, hauling a horse trailer, or rolling coal and making noise to impress their friends. We are in two very different applications with different needs, even if the motor parts may interchange somewhat.
ATF and engine oil are two completely different engineered fluids designed for different things. If you could swap-in some Delo for Transynd, every school district in the nation would be doing it.
Fwiw, I have actually used synthetic oil in a trans. I used to race a VW Rabbit in SCCA GT3 in SoCal. Shift points were 8400 rpm and we got 200+ hp from 1600 ccs in a stock-based block. When Mobil One synthetic oil came out we jumped on it and stopped running over crankshafts. Awesome stuff. Then the Mobil rep told us to use it in the trans (5-speed manual), and we did. Worked great... As long as you changed it after every event because it sheared down fast. Talked to ANOTHER rep who suggested using ATF with a zinc/moly additive. This worked so well we never changed the fluid again. (Of course, the life of a transmission at race speeds was maybe 500 miles).
Back to the issue at hand: A complete fill of an Allison with TES-295 compatible fluid is less than $400 complete with filter and beer. The cheapest quality rebuilt trans for my bus is about $3500 sans labor.
I'll stick with what the factory recommends and leave the pretty bits of twisted metal on the coffee table for the Dodge Boys.
Experimenting is fine when you can just toss a broken vehicle onto a trailer and take it home for repair. Not so much when you weigh 12 tons and a tow is going to empty your wallet and piss-off the Missus something awful. Lol...