I have a 53 flathead 8 with 3 on the tree.
I know nothing about transmissions. I had mine worked on (new seals and some gears replaced) while the engine is being rebuilt....

I am wondering how an overdrive works? Is it an add on? Could I find one and "simply" bolt it on? I am trying to stay close to stock, but the 32 rear end won't be great for the highway.

Just noodling...
It's cold.

 

There have been some really great recent discussions about overdrives on the trucks. I believe (and I haven't checked again but seem to remember) that an overdrive transmission came as an option on the 53s.

The original units were made by Borg Warner. The ones made for Mercury were a little longer - physically.

There are after market overdrive units that you can "bolt on the back," but the stock overdrive transmissions are fairly plentiful, as are most of the ELECTRICAL components needed to work the transmission.

There is a relay, gas pedal kickdown switch; solenoid; and governor.

Usually folks selling the transmissions sell them with the governors and solenoids still attached to the transmission. The kick down switches are available all over the place. It's the relays that are a little tough to get - especially if you have converted to 12 volt. 12 volt relays are IMPOSSIBLE (or almost) to find. You'll probably have to step down some power to 6 volt to run the overdrive just because of the relay (6 volt).

Here are a few prior threads on overdrive. I also have all the Borg Warner Manuals on PDF files if you need them.

https://www.ford-trucks.com/forums/6...sion-work.html

https://www.ford-trucks.com/forums/7...l-3-speed.html

If you have any other questions, feel free to ask anytime!

Julie

 

Julie,
Thanks, guess I'll start keeping an eye on ePay.
My truck is 6 volt, so shouldn't be a problem there.

Steve

 

Steve, The T85 transmission, which was the overdrive option from 53 to 56 are hard to find. If you can't find one, you might consider using the T86 which was the overdrive option from 57 up into the sixties. They are easier to find. I am using one for my 53 flathead. It bolted right in but I had to make a clutch pivot out of angle iron because the t86 doesnt have the access lid on the side like the t85 with the pivot mount. The t86 has the access lid on top.

 

To make the BW overdrive work on a stock Trans you need to drill a hole in the back of the tranny case. Its not a big deal unless you have ten or so thumbs.
Stay away from the Merc and or Convertable OD units the solinoid placement doesnt work due to the crossmember location.

Oh did I forget to mention that the Trans main shaft (Output) is different?
It is shorter on the OD Trans.

EDIT: Go here for all the BW maintenance books FREE in PDF
http://speedprint.com/deves50/overdriveindex.php

 

Thanks all, if anyone knows of one let me know.

 

Hi Again!

Heres a few e-bay links to a transmissions and the electrical components I talked about. If nothing else you can look at or save the pictures for future reference.

Here is the Governor (which is actually mechanical in nature - spinning counter weights and closes an electrical contact at speed):

eBay Motors: 1949-1960 Ford,Thunderbird,Mercury overdrive governor (item 350154454643 end time Feb-15-09 17:29:14 PST)

OBTW that is WAY too much to pay for a governor.

Here is a solenoid:

eBay Motors: 1949/1950/1951 Mercury/Ford Overdrive Solenoid (item 330300867553 end time Jan-21-09 19:02:51 PST)

And again, that is way too much to pay for a solenoid.

Here is a kickdown switch:

eBay Motors: 1949 50 51 52 53 1954 Ford Mercury Overdrive Switch (item 220335073614 end time Jan-25-09 05:21:23 PST)

OK price probably avail at NAPA for less.

And a relay:

eBay Motors: 1956 ford overdrive kick down switch, relay, and cable. (item 120365605943 end time Jan-25-09 13:36:10 PST)

VERY GOOD PRICE so far.

And a complete transmission:

eBay Motors: 1949-64 FORD OVERDRIVE TRANSMISSION FLATHEAD HOT ROD (item 370147755664 end time Jan-27-09 08:24:03 PST)

Note the governor on the left tail of the transmission and the solenoid on the right center.

Good Luck,
Julie

 

They also make an overdrive unit that bolts between the bell housing and manual transmission.

I don't know if it will work on the early type of trans, though.

But they are very expensive.

Ranger Torque Splitter Overdrives & Underdrives