The Stovebolt Site Forums The Shop Area Driveline Borg R10 overdrive question

Just wondering if anyone has link to literature explaining theory/operation of a overdrive on Muncie 319. Read some older literature on subject in past but can’t find the links anymore. Thanks, Mike

Try this one- - - - -it's on a Ford site, but the Borg-Warner OD unit was the same, no matter what vehicle used it. I've got a 1960 Rambler American station wagon with the same OD unit. My 1954-62 Chilton service manual has about 4 pages of information on the B-W overdrive unit, also.

http://www.fordification.com/tech/overdrive.htm

Jerry

Once you understand how they work and you drive one you will be amazed how seamlessly they actually work. I love mine and it amazes me how well it works.

I drove a 52 Nash Ambassador with OD back in high school- - - - -won a few sucker bets with my friends who didn't believe I could get 6 speeds out of it!
Jerry

I put one in my ‘61 Jeep with 5.38 gears, worked well.

I saw one yesterday in a wrecking yard hooked to some kind of Dodge or Plymouth.

Ed

Ed, it's more likely what you saw was a "Gyro-Matic"- - - -a 2-speed manual transmission used by Dodge with an electric shift overdrive that gave the vehicle 4 forward speeds if the driver used a creative shifting technique with the kickdown switch. Chrysler ran the same basic transmission and called it an "M-6". The transmission had low and high manual shifter positions, and used an electric overdrive similar to the Borg-Warner system to give each range two speeds. It also had a fluid drive coupled to a manual clutch that would allow the engine to idle in gear and be driven like an automatic in traffic. I drove a 1951 Chrysler coupe with the M-6 transmission when I was in high school in the early 1960's.

https://www.allpar.com/threads/the-odd-m6-and-m4-four-speed-semi-automatic-transmissions.229925/

Jerry

Jerry,

Could be, I didn’t inspect it that closely, if someone wants it, I could find it again.

Ed

It was a nightmare to work on 50 years ago, and I'll bet the thing hasn't improved with age. The fluid drive had a spring loaded ceramic mechanical seal like what's in most water pumps, and they were notorious about failing and leaking all the fluid out of the drive unit. The terribly heavy transmission, clutch, and fluid drive unit had to be removed to change the seal, and then reassembled very carefully to avoid damaging the new seal. I finally figured out a way to lock out the fluid drive on my Chrysler with some creative welding, and drive it like it had a normal clutch, which made a noticeable improvement in the performance by eliminating the built-in slippage of the fluid drive.
Jerry

R10 Info:

Borrowed from the Internet:
The only overdrives which ever came on GM cars were R10 units which were bolted to the (4 bolt side cover) Muncie transmission SM319 or the later Saginaw trans (7 bolt side cover) SM326. You will find "R10" cast into the OD housing followed by a letter which indicates the original application. Following are the letters I have found on GM units so far. This is not to say there aren't others.
H - 55-57 Muncie w/o rear mount - 16 spline output
K - 58-63 Muncie with rear mount - 16 splines
P - 64-65 Muncie - 27 spline output
Q - 66-69 Saginaw only - 27 splines

Limited time preview of operator's manual on this website:
https://www.scribd.com/document/433324460/bwoperators-pdf

Buoymaker,
The information you provided is not totally accurate with regard to the 64 & 65 Muncie/R10P OD units. None of the internal gears, syncro, and overdrive main shaft will interchange with the earlier models. They have a different pitch on the gears. In fact the transmission case is slightly different as the cluster gear is longer and will not fit in the earlier cases. There are two versions of this unit, a standard version and a more heavy duty unit with different gear ratios. This series is also referred to as a WG295.
The P case is also different as it uses a different (smaller diameter) governor and a different gear..

In addition many of the R10 H cases came with a rear mount.

Fred

I have been messing with BW overdrives for over 60 years and it is still my favorite transmission. I prefer to have them behind a BW or Saginaw transmission, but they will do wonders behind a SM 318 with 3.89 or 4.11 rears. It doesn't make any difference if you have a chevy with a Muncie with an OD behind it or a BW transmission with an OD behind it in a Y-Block. They are really fun to drive. Very little goes wrong with the OD as long as you keep oil in them. I have driven them, torn them up and rebuilt them. I still have a lot of spare BW parts.

https://photos.app.goo.gl/xaJzGqqyzwPs2GqH7

Maybe some day I will be rebuilding them again.

Her is a link to a service manual.


https://documentcloud.adobe.com/link/track?uri=urn:aaid:scds:US:b1d2777f-0f56-48fc-8922-a45fdbb8cf51

As for the Plymouth, it could have a BW OD or it could be a Fluid Drive. My father bought a new 1949 DeSoto with fluid drive from his brother. I hated the thing, but the transmission outlasted everything else on the car. My cousin still sells Chrysler-Jeep-Dodge. If you can't get under the car to look an OD will have a lockout handle under the dash and usually have overdrive written on the trunk. Some of the parts interchange between different R10 ODs and some don't. I usually just compare parts.

Another overdrive that was popular on Brit and European vehicles was the Laycock unit. It can be found on Jaguar, Triumph, Austin-Healey, Volvo, and a few others. It's the basic unit that's used by Gear Vendors for their add-on OD systems. That one has a built-in hydraulic pump to provide the OD functions, and a solenoid to turn the hydraulic pressure on and off. With a little creative machining and the addition of a crossmember to mount it on, a Laycock OD can be installed as a divorced unit similar to a transfer case, or a Brownie on a big rig.
Jerry

I just bought a M219 from Tom Langdon and swapped it into my 56 210 car, replacing the factory 3-speed M218. The orientation of the shift levers are different. I had to swap the side covers from old to new. Tom Langdon is skeptical that I will have reverse, but we shall find out soon. The internals on the side covers looked identical.

If you've still got 4 shifter positions on the column linkage, you'll have reverse, but it might not be in the traditional position in the "H" pattern. I think that swapping side covers is going to be a bad idea if it changes the shift pattern. The rear linkage is the reverse/1st. gear shifter, and if the direction the bellcrank is pointing is different, the location of 1st. and reverse will be swapped.
Jerry

There are numerous side covers and different clock positions for the levers depending on the year, model, and if it is from a car or a truck. That doesn't change the 2-3/1-R locations. It is quite common to have to use your existing side cover when making the switch. That series Chevy overdrive is an SM319.
Fred