[WVengr]

I stumbled across something and was wondering if there is something like this out there today, and also if it would be worth the extra mechanical complexity and weight on the car.

I own a 1958 Edsel Ranger, and was browsing through the original shop manual I have when i saw a section for "overdrive transmission". curious, I started reading it and it seems to me that this was a fairly strange setup. Right after the engine, there was a normal 3 speed manual transmission, as was common at the time, but the magic occurred after the 3-speed. Attached in the back of the transmission case was the "overdrive unit" this consisted of a electrically shifted 2 speed gearbox that could be either direct drive (1:1) or overdrive (0.7:1). It would automatically shift into overdrive at higher speeds to conserve fuel. There was also a "Overrunning Clutch" between the transmission and the overdrive unit that allowed the transmission to apply power to the overdrive, but not the overdrive to the transmission, essentially allowing the car to coast in neutral by simply letting off the gas rather than actually shifting. This of course could be locked out by a control knob in the drivers seat if you were needing to slow down using the transmission and engine like on a steep hill.

Unfortunately my example has an automatic transmission, so I cant test it out in the real world, and from what I have read this option was extremely rare, something like less that 2% of the cars built. Give that they only built 60,000 that comes out to about 1200 cars, most of which probably don't survive today.