Jump to content

1940 P10 Transmission


Recommended Posts

Hi All -- First ever post... I have a 1940 Plymouth Deluxe that is pretty much entirely original. It has the original 201cc and 3-on-the-tree transmission. I would like to upgrade the tranny to try to eke out a reliable 55-65mph top speed. Is this possible while maintaining the original engine? Is there an overdrive that would pair relatively easily with the 201 and 3-speed?


1940 Plymouth.jpg

Link to comment
Share on other sites

Likely that one has a 4.1 but if it retains it's original 16" wheels it should be the same result as your 51. 


You need to rig up a tach and see what RPM you're really at before changing anything 

Link to comment
Share on other sites

In May of 1952 Plymouth began using the Borg-Warner R10 Overdrive.

Your 1940 is the first year of “3 on the tree” so yes it will fit.

You can check the rear end gear ratio online for you car and double check it under the car.

The housing has the ratio stamped under the filler plug.

Ratios are available to 3.54 which with an Overdrive would need a strong engine or a light car.

It is my personal opinion that a properly working R10 Overdrive really benefits a Plymouth.

Even at 55 mph the car is so much quieter because the rpm drops 30% in Overdrive.


BTW don’t throw away your 1940 transmission. That’s the one with desirable 2nd gear ( the only optional gear ratio in 2nd )

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.

Terms of Use