Overdrive
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Tom Endy
Well-known member
Borg Warner conversions came about before factory made overdrives became available for the Model A. They are cumbersome to operate. If you install one with the governor circuit hooked up it will prevent damage when attempting to back up and will prevent the battery from becoming discharged if you inadvertently leave the power switch in the on position.
The biggest problem with a Borg Warner is that most use the Model A rear axle grease seal as an oil seal at the output of the overdrive and oil can migrate past it. Oil will migrate into the banjo without the owner's knowledge and eventually starve the overdrive of oil and it will self destruct.
There are plenty of them sitting around, most in a failed condition. Best to install a factory build Mitchell overdrive. It is well made and comes with a warranty.
Tom Endy
The biggest problem with a Borg Warner is that most use the Model A rear axle grease seal as an oil seal at the output of the overdrive and oil can migrate past it. Oil will migrate into the banjo without the owner's knowledge and eventually starve the overdrive of oil and it will self destruct.
There are plenty of them sitting around, most in a failed condition. Best to install a factory build Mitchell overdrive. It is well made and comes with a warranty.
Tom Endy
Bob-A
Well-known member
My '29 roadster came with a Borg-Warner. First time for me for an over drive. I love it, but I would probably love a Mitchell gear splitter type of O/D even more!
I've had some close calls when it comes to backing up with my B-W
. So far so good.....pay attention to what Tom Endy says and get a Mitchell.
Bob-A
I've had some close calls when it comes to backing up with my B-W. So far so good.....pay attention to what Tom Endy says and get a Mitchell.Bob-A
TerryH
Well-known member
If I remember correctly, the BW is also about 30-33% OD, which is too tall for some folks. The Mitchell is 26% which to me seems about ideal. I have had one in my Town Sedan for about 6 years and would never have another A without one........works very well and you will have no issues with it.
Brother Hesekiel
Senior Member
My car was ground-up restored a long time ago and came with Borg Warner overdrive and 4:11 gears. In town I never have to use the overdrive, but once the speed exceeds 45 or so, I pull up the lever to have the overdrive on stand-by, then flip the O/D switch when the opportunity arises and I want my Roadster to stretch its legs.
A bright red control light next to the switch would prevent me from backing up with the actuator engaged even if I was drunk like a skunk. As long as you don't back up, the overdrive can be engaged all the time, even at very low speeds. The difference in driving with the 0/D versus driving without it is that there's no engine braking if you back off the gas. The car basically coasts. That's not bad at all, but it makes you aware that the overdrive is engaged when coasting toward a red light or Stop sign.
http://www.fordification.com/tech/overdrive.htm
http://www.ocmafc.org/techarticles/Tom%20Endy%27s%20Special%20Topics/Borg%20Warner%20Overdrive.pdf
You could say that the Borg Warner is period correct, or at least more period correct than anything else. I also have a 1939 transmission in my car, and giving the cost of the Borg Warner plus the 3-speed synchro transmission, plus the 4:11 rear end gears, all of which requires major work, I would not go with a Mitchell but either a Ford F-150 transmission or even a T-9 5-speed transmission instead and catch 3 birds with one stone if I had to start from scratch.
A bright red control light next to the switch would prevent me from backing up with the actuator engaged even if I was drunk like a skunk. As long as you don't back up, the overdrive can be engaged all the time, even at very low speeds. The difference in driving with the 0/D versus driving without it is that there's no engine braking if you back off the gas. The car basically coasts. That's not bad at all, but it makes you aware that the overdrive is engaged when coasting toward a red light or Stop sign.
http://www.fordification.com/tech/overdrive.htm
http://www.ocmafc.org/techarticles/Tom%20Endy%27s%20Special%20Topics/Borg%20Warner%20Overdrive.pdf
You could say that the Borg Warner is period correct, or at least more period correct than anything else. I also have a 1939 transmission in my car, and giving the cost of the Borg Warner plus the 3-speed synchro transmission, plus the 4:11 rear end gears, all of which requires major work, I would not go with a Mitchell but either a Ford F-150 transmission or even a T-9 5-speed transmission instead and catch 3 birds with one stone if I had to start from scratch.
John LaVoy
Well-known member
I installed the Borg Warner overdrive on the phaeton in the 70s and have logged somewhere close to 100,000 miles on it. Like was said you need to be sure it is topped off with fluid but they work nice. The downside is not being able to engage the overdrive while going uphill so you can't shift to 2nd overdrive from third. I say put it in and get on the road!