overdrive transmissions

[MATT44]

I am looking to purchase a 1937 Plymouth Sedan that has a stock 3 speed manual transmission with the (top loader) shifter on the floor.

I heard that you can only add an overdrive to this car if it has a steering column shifter.  Does anyone know if I can add a overdrive unit and where I might find 

that overdrive unit?

[Mike36]

7 hours ago, MATT44 said:

I am looking to purchase a 1937 Plymouth Sedan that has a stock 3 speed manual transmission with the (top loader) shifter on the floor.

I heard that you can only add an overdrive to this car if it has a steering column shifter.  Does anyone know if I can add a overdrive unit and where I might find 

that overdrive unit?

You do not need an overdrive unit. You need a transmission with attached overdrive. Overdrive cannot be added to your transmission. 1935 thru 1939 will work from a Chrysler or Desoto. If using a 1939 unit, the top cover and shifter from your 1937 transmission will have to be installed on it. Your driveshaft will need to be shortened as the overdrive transmission is longer. This is a fairly simple bolt in change. Be aware, these are mechanical overdrives without a kick down solenoid. Vehicle must be slowed to around 35 mph to go out of overdrive. You must have parking brake in good working condition when you have an overdrive transmission.

 

 

[pflaming]

Mike, will the R10 overdrive transmission attach to the 39 bellhousing? I believe it will. 

Edited June 23, 2018 by pflaming

[Mike36]

I am not sure, but think it will. Many years ago I put a 59 Plymouth engine in a 50 B1 with a 4 speed, and put a 49 Dodge engine in a 36  Plymouth. This suggests interchangeability over many years. Believe it or not, the driveshaft from a 49 Ply 4 dr is the same length as one from a 36 Ply coupe!

[pflaming]

Per my recollection, in around 1939 BW made some improvements internally, yet the housing did not change. I have fabricated a floor shifter for my R10 and the standard three speed transmission. 

[The Oil Soup]

Here is another option. http://p15-d24.com/topic/44138-laycock-j-type-overdrive/

 

[Magnus]

I have a Dodge from -36. I have installera a R10 from -52. These transmissions are not build for floor shift but I rebuild it so it became one. It’s not so complicated. I also need to modify the emergency break and shortened the driveshaft as well.

Edited June 23, 2018 by Magnus

[Mike36]

Good job Magnus. I had not heard of anyone doing this.

[greg g]

And the prize for Creative use of Bellcranks and Heim Joints in a supporting role goes the Magnus!

 

You could probably sell a few of those with the number of folks who would like a floor shift.

Edited June 24, 2018 by greg g

[Magnus]

Thanks for your positive feedback!

[MATT44]

On 6/22/2018 at 9:54 PM, Mike36 said:

You do not need an overdrive unit. You need a transmission with attached overdrive. Overdrive cannot be added to your transmission. 1935 thru 1939 will work from a Chrysler or Desoto. If using a 1939 unit, the top cover and shifter from your 1937 transmission will have to be installed on it. Your driveshaft will need to be shortened as the overdrive transmission is longer. This is a fairly simple bolt in change. Be aware, these are mechanical overdrives without a kick down solenoid. Vehicle must be slowed to around 35 mph to go out of overdrive. You must have parking brake in good working condition when you have an overdrive transmission.

 

 

 

[MATT44]

Thanks to all very helpful 

Matt44

[pflaming]

Here is my R10 overdrive transmission with a custom fabricated floor shifter attached. It is mechanically sound now needs some cosmetic milled parts.

[Lloyd]

On 6/22/2018 at 9:46 PM, pflaming said:

Mike, will the R10 overdrive transmission attach to the 39 bellhousing? I believe it will. 

 

I have a 39 P8. I swapped the original 201 with a 1950 218 and used the original bell housing from the 201. I know an R7 trans bolted up to the bell housing. The only problem I considered was my 39 had a cable actuated shifting mechanism which was unique to 1939. This meant I had to swap the steering column with a later model to get the standard shifting linkage. Any of the later column shift linkage would have fit the R7 and from what I was told the R10 as well. I then got an R6 OD. This was the OD trans available for the 39 and previous years. Then I swapped top plates from my original to the R6 and it bolted right in. The R6 I got originally came with a floor shifter. 

Not sure what kind of shift linkage a 37 has - does your original trans have a bolt on top plate or 2 shifting arms on the side? I would guess if you go with a floor shifter you should be able to use the R10. I would. May have to get the shifter to if your original had a top plate. 

Honestly I don’t see how it could be true you have to have a column shift to put an OD in. Lots of guys on here have an OD on the floor.

 

Here’s a pic of the R6 with the top plate and cable shift.