Yet More Borg Warner Overdrive Information - Solenoid and Relay Part Number ID.

Just when you thought it was safe to go to the garage, that you had all of the information there was available about the Borg Warner overdrive...well there is more. I have been on a constant quest to gather up all of the Borg Warner Overdrive information that I can find. I now have found most of the overdrive solenoid part numbers as well as most of the relay numbers and some technical information about each of those.

First up you need to know is that there were three manufacturers of overdrive solenoids, BMC, Autolite, and Delco. The BMC company it appears made the solenoids for Borg Warner. Nobody seems to know if BMC was a Borg Warner Company or somebody they contracted with to build their solenoids. With eleven different car companies offering the Borg Warner Overdrive as an option plus the aftermarket demand, made it very difficult to keep up with solenoid production.

Borg Warner sold over two million overdrive transmissions by 1950, and would go on to sell over four million by 1970. No wonder they were busy.

You should know by now that most all of the solenoids will interchange between the different models, as long as you keep the same voltage and shaft length. I am putting this OEM Part Number information up in case you run across an original NOS solenoid or relay, you will know the original application.

Keep in mind that with solenoids, that the cover end with the part number often got damaged when the transmission was placed on a concrete shop floor during a clutch job. An easy replacement the end covers got swapped out for an undamaged replacement. My point is you can not always assume the cover on the back of the solenoid is the original. After 60 plus years a lot can happen to a solenoid.

This page came from an old overdrive service book that is way older than I am, and no doubt older than most of you. So excuse the poor quality, the book had been well used and abused by the time I found it. You can click on the picture to make it larger.

I also have the same information for the overdrive relays. Again same story, you know all of the overdrive relays will interchange as long as you keep the voltage the same.

There is also some technical troubleshooting and related information on both of these pages. The wiring diagram is clearly one before 1951 because it still shows the reverse lockout switch.
Same deal here...click on the picture to make it larger.

Some solenoids were built with wires coming out of the terminals, while most had screw terminals which made it easier to remove the solenoid for replacement. While there were a few additional variations most all of them can be converted to the more common four post relay and two post screw terminal solenoid of which new replacement parts are readily available.

No matter the combination all of the Borg Warner R-10 and R-11 overdrive solenoids function the same way.

Stay tuned for more... as I find it I will share it with you here....