Stumbled upon an old school idea

[4more]

corvette had them in the mid 80s. it was a 4 speed manual with an overdrive unit by push button. they called it the 4+3 trans

[texanidiot25]

GearVenders is really the closest thing you'll get to that setup, it's an add-on overdrive for 3spd autos. However, if you're simply looking to convert your Edsel to overdrive, you're just a modern transmission swap away from it. OD transmissions have been the standard since 80s. Thankfully, with Chevy cars it's as easy as swapping in a 4spd 200R4 or 700R4 from the gang of RWD GM cars and trucks in the 80s, but Ford doesn't have that commonality with engine bolt patterns across their line of cars, so I can't tell you what'll fit the FE motors.

But, there's almost always a solution, and if it came to an adapter plate to put a ford block to a Chevy bolt pattern, you have a fairly cheap solution to a great OD trans.

[WVengr]

Wasn't exactly looking to convert the Edsel to overdrive, since it hasn't only sees 70mph a few days a year, and I am dropping the rear end gear ratio to something more efficient. Also if i was swapping any tranny into it it would be a manual. I hate driving automatics, but I couldn't find a manual Edsel and love that car enough to put up with the transmission.

I was just thinking that something like this would be nice in my truck. The tranny in it is already overdrive in the 5 speed, but the rear axle ratio is so steep that it sits a something like 3000-3500 rpm at highway speeds, but would be great if I could have a better ratio for just normal interstate driving, but not have to give up the good ratio for hauling.

[gone-ot]

...the Ford O/D-unit was wholey contained in the tail-shaft assembly of the 3-speed manual gear boxes, so check your "older" junkyards.

...I believe the Ford O/D was actually made by Borg-Warner, but I'm not sure. It was electrically (solenoid) controlled.