The Stovebolt Site Forums The Shop Area Driveline 1957 Overdrive

Does the Borg Warner R10 overdrive transmission governor gear have 15T or other?

Does this help? http://chevy.oldcarmanualproject.com/booklets/5513topindex.htm

Or this? http://chevy.oldcarmanualproject.com/shop/1955truck2/55ctsm0715.htm

I have one I can count this weekend. Fred in CA might also be able to help.

Thanks, Frank for the info. I have both docs and have gone through both without any success to locating my answer. My dilema is that I have a Muncie 319 overdrive tranny which is missing the governor.

I have a NOS governor after much searching, but DO NOT HAVE the gear which mounts on the governor shaft. I am trying to locate one in good condition, but find the ones produced by BW, I have seen already vary in the number of teeth based on the specific vehicle application (vehicle make/model) since BW made these for multiple car makers.

Still looking for some help!

Thanks, Mapleleaf for your help. Can you pass this question onto Fred in CA for assistance?

I am guessing the number of teeth on the gear determine the speed at which the governor grounds the solenoid circuit. As shown in the manuals, the speed of OD engagement varies with different vehicles. I imagine the gear you have will serve you well even if it doesn't kick in exactly at the same speed a Chevrolet spec one would.

So, I could use a 15t gear without damage to either the overdrive unit or the governor?

I thinks so. Study this info on the OD and how it works and I think you will agree.

All the governor does is ground the solenoid circuit when operating speed is reached and opens the circuit when speed drops below operating speed.

This got my curiosity up so I pulled the governor off my spare. It has 20 teeth. The gear is stamped IRIOH-73.

Now my thinking has changed. If it were one or two teeth difference it might be OK. From 15 to 20 teeth is quite a jump. Less teeth is going to spin the gov. faster, meaning you will engage OD at lower speeds. And of course hold it in OD at lower speeds as you slow down. I believe I'd look for a 20 tooth gear.

It does indeed use a 20 tooth gear with the markings as Cletis stated. It also has a shaft that fits into a 1/4" hole in the case. The gear that drives the spedo & governor is metal so I doubt that you could use anything but the correct Chevy gear.
If it is not matched it could possibly destroy both gears. Ford, Mopar, and Studebaker governor gears are all different from each other and the one you need. BW produced OD's for a wide range of OEM's but the only common thread was many of the internal parts and operational characteristics. Housings are specific to each OEM.
Fred

Thanks for the information. I have the governor...but my search for the correct gear goes on in order to make my overdrive truly complete and correct.