Unknown Overdive

raventrone

raventrone

Junior Member
I bought a 1931 Model A Fordor slant windshield sedan two weeks ago that has an overdrive. It does not work and never did for the previous owner, who had the car for 15 years. It is controlled by an attachment to the shift that has an on/off switch and black pull lever in which the word "overdrive" is recessed in white.

Does anyone know who manufactured it and where I might get information on how to repair it and how it is operated? Thank you.

Richard Ventrone
Glocester, Rhode Island
 

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It looks to me like a Borg-Warner OD from the 1950's or '60's.

Look on the driver's side of the case for raised numbers cast into the case, an R followed by a number. This is the model of the OD.

I would expect it to be an R-9 or R-10.

If this is the case, it is a "full electric" OD, which uses the governor and solenoid to achieve the upshift into OD, and hold it there.

The kick-down ( if any ) or dash switch disables the solenoid, and the unit shifts down.

The lever and cable are a manual lock-out. I think when the lever on the OD unit is pulled forward, the unit is in lock-out (direct drive).

Is your car 6-volt or 12 volt ? (post 1955 OD's would have been set-up to operate on 12 volts...)
 
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The governor at the rear sends the ground signal to the relay (mounted in your crossmember), which then sends voltage to the solenoid to pull in the overdrive. My Studebaker governor has a 4.56 rear end and sends the ground signal at about 30 MPH. If this Model A has the stock 3.78, then the ground signal will come at a higher speed.

Since this is not bolted to the original ******, there is no automatic lockout for when you shift to reverse. If you shift to reverse while still in overdrive mode, you can damage the overdrive unit, and that's probably what happened here.
 
Go to the web site of the Santa Anita A's of Arcadia, California at www.santaanitaas.org. On the home page put your cursor on "Technical Reference", my name will drop down below, click on it. A menu of articles will come up. Scroll to the ones on overdrives. There are several articles on the Borg Warner overdrive. You are welcome to down load and print out any of them.

There are three things to check with the overdrive installed in the car. Check the oil level, check that the pull cable moves the lever to the stop at each end. Check that the solenoid works. You should be able to hear it click if it works.

Tom Endy
 
I like the way they work,but the gearing is just a little high for me.I don't know if they are all the same or not.The ones I've seen were 33%.I have 6 or 8 transmissions with those units still on the rears,and I have to do a little investigating to see if there were any versions with lower gearing.If I have a lower geared one I will have one built with it.The yard I worked at in the mid 70's has a lot of old truck bodies we stashed stuff in,and they are cleaning it all out.I grabbed all the OD transmissions I could find,we think there are more in there.
 
In the 1980's, a fellow in Manteca , Ca. named Bob Bell used to install and assemble the Rambler or BW OD's with a lock out lever/rod from the OD to the top end of the A ****** that would automatically lockout when going in to reverse. Perhaps some one has info. on how that's done.
 
Hello,
I just bought a 30 coupe a month ago and has same over drive in it. It works great ,except the governor is not hooked up. I just push the T handle down and when I want the overdrive to engage I turn on the toggle switch and it sends power to the solenoid and as rolling down road in third gear after I energize the solenoid with lever all way pushed in you have to let off the gas and you feel it shift like a automatic and it is in overdrive and speedo goes from 40-45mph down to 30-35 mph. It works great. I would defiantly go to the website for the car club ion California very good directions because if you try and go in reverse with energized and t handle down can rune the overdrive unit. I have to say I love having the overdrive the car goes down highway at about 55mph or so.
 
Speedyal said:
Hello,
I just bought a 30 coupe a month ago and has same over drive in it. It works great ,except the governor is not hooked up. I just push the T handle down and when I want the overdrive to engage I turn on the toggle switch and it sends power to the solenoid and as rolling down road in third gear after I energize the solenoid with lever all way pushed in you have to let off the gas and you feel it shift like a automatic and it is in overdrive and speedo goes from 40-45mph down to 30-35 mph. It works great. I would defiantly go to the website for the car club ion California very good directions because if you try and go in reverse with energized and t handle down can rune the overdrive unit. I have to say I love having the overdrive the car goes down highway at about 55mph or so.
Click to expand...


The advantage of having the governor connected to the solenoid circuit is that the solenoid will only actuate when you are above a nominal 35 mph. This will prevent you from attempting to back up with the solenoid powered and doing damage to the to the overdrive unit. It will also prevent you from parking the car for the day with the solenoid powered and running the battery down

It also allows the overdrive to automatically go into and out of overdrive at highway speeds by itself. When traffic causes you to slow down it will drop out of overdrive when under the govern speed (35 mph), then go back into overdrive when you are able to increase speed above the govern speed. You can actually increase the govern speed by stretching the spring inside the governor.

The governor is merely a switch with one side to ground. When the switch closes at the govern speed (about 35 mph) it provides a ground to the bottom side of the solenoid and it allows it to actuate.

Tom Endy
 
Tom makes a good point about the OD function... this version was the last stage in evolution for the B-W overdrive.

The first OD's back in 1934-'38, were "full mechanical" - the "cut-in" speed & function were entirely controlled by centrifugal weights inside the unit.

The next generation, '39-'42-ish were "semi-electric", which still employed the internal centrifugal weights for cut-in, but a kick-down solenoid and relay were added for "passing gear".

And finally, the "Full-Electric" OD was introduced around 1942- end of B-W OD. These units added an external governor, and changed the function of the solenoid from "kick-down" to "cut-in" / "upshift", as Tom noted above. These are the R-9 / R-10 / R-11 units.
 
Cleaning out the garage and found this in my grandfather's toolbox and thought it might help. He was one of the original manufacturers of the BorgWarner OD for the Model A.
34be3f94c4532606f36429a37d32b319.jpg



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