So my '59 is at the transmission shop waiting on a complete rebuild. When I bought it, I was told it was equipped with an overdrive transmission, but the cable had not been hooked up. I asked the transmission shop to see if they could get the overdrive working. It would really improve my gas mileage.

Has anyone else been through this before? Have any insights, do's and don'ts, words of wisdom about the overdrive feature on these 3 speeds?

 

I hope your shop has someone with experience with these overdrives units
( read one of us old guys ). Besides the mechanical part there is an electrical circuit with a relay, kickdown switch, solenoid and governor. Many of these parts are getting hard to find and are expensive when you do. When working properly they are great, I've used them in several passenger cars and have one in my F100..

 

You could get away without some of the electrical stuff... it's designed to kick down into normal drive when you floor the gas. But it wouldn't be too hard to adapt a common relay and a momentary contact floor switch (starter? horn?) if you don't have the originals. If you need the lockout cable assembly, those may still be available from Ford truck specialists. (I bought one around 1990, although the plastic handle looked like a different type of plastic than would have been used originally.) I only took one test drive with the O/D transmission, since something went wrong when I reassembled it and the cases didn't seal properly. That particular transmission wasn't from a Ford, and has since gone to the scrapyard. (I did save the solenoid and governor.) I scored an allegedly Ford 3 speed/OD from a swap meet, but haven't tested it out yet.

For a working truck, it might be wiser to install a truck 4-speed (with the granny 1st gear), or spend the bucks for a modified bellhousing to fit a modern overdrive transmission. I've encountered a couple of hills that couldn't be climbed with a loaded truck in 1st gear with a light-duty 3-speed. One hill could be avoided; the other I backed up and took a run at.

 

Recent discussion with some links to parts etc. OD ratio was .70 or .72, allowing a shorter rear axle such as 3.89 or 4.11 etc or even 4.89s.

https://www.ford-trucks.com/forums/1...a-cruiser.html