The car companies sourced overdrive units from several companies in the '50s and '60s - some were completely manual, some used electric solenoids, some a combination. Some were attached to the tailshaft housing of the transmission (I think the '55 Ford used a Borg-Warner unit mounted there); some overdrives were part of the rear axle assembly (later 1960s Fords and possibly the Studebaker). One such product was the Hone-O-Drive.
Whenever I find a junkyard with some old pickup trucks, I peek under all the '60s and early '70s Fords - those seem to be the last place that those axle-mounted units were used. They are worth $$$$ to the hot-rodding community, the now rare examples bringing ten times their original price of $300 - $400. Nowadays, though, not many junkyard workers know what those things are. I'd buy the entire axle unit, if necessary, to get the overdrive.
That is interesting.
I am not sure what ever happened to my old 55. The last I saw of it, I traded it to my Uncle for a hog which my parents butchered.
I rode in it maybe two years later and Uncle Milton had spent a little money on it and had it running good again. Don’t remember what he ever did with it but he died maybe 20 years ago.
I always had a soft spot for the Ford 272. Only 164 horsepower but it was a running machine.