1939 Plymouth Coupe

[Richard Cope]

Hi 

I have a 1939 Ply Business Coupe, all stock.  It was restored body off about 8 years ago.  For safety currently in the process of upgrading front brakes to disk and change to dual master cylinder.  Also considering adding a Mitchell's overdrive 1000 with a push / pull lever.  Any one had any experience with this set-up?  Two gear ratio's are offered: 26% and 36%.  I live in N.J. , basically flat.  Need the over drive when I run on intestates.  The car will currently run at 50 - 55 mph comfortable and 60 for short periods however engine is starting to get tight and wouldn't want to run at that speed long.  Inorder  to keep up with traffic, would like to run 60 - 65 for 10 to 20 miles.  Any thoughts on which ratio would be best.  

I contacted Gear Vendors several times, however have been unable to even get dimensions of their product.  Figure if they won't send me dimensions, if I ever had problems they wouldn't be much help.

 

 

Appreciate your thoughts.

Regards,

 

Richard

[casper50]

Very nice coupe.

[comedtech63]

Sorry this question is off the topic , what color is on your car , very nice color

I have a 40 coupe dodge that I will be painting soon

[Richard Cope]

Where to I put my question so that it is with the topic.  The color is Volvo Midnight blue, It is a perfect match for Aviatior  Blie used in 1939

[comedtech63]

It was  me that was off the topic  with the color question , it just looks so good with that color

Thank you  for the answer

[Ranger]

Welcome! No experience with your question but I'll follow along. My '36 is also very low geared and would benefit from an overdrive. Great looking car.

[dpollo]

If your car has the column shift, my first choice would be the R10 overdrive as used from 52 to 56.

Some modification of the shifter low reverse selector cable  will be needed and the driveshaft would need to be shortened.

 

Chryslers in 39 used a semi electric overdrive which evolved from the  overdrives used in 35, 6 7 and 8 but with an electric kick down.

This unit can accommodate the floor shift.  This would be my second choice.  Export models of the 39 Plymouth were equipped with this OD

which I believe was either R6 or R8

 

The final drive speed reduction in both units is approximately 30 %.

[Mike36]

I have a R6, no electrics on it. 100% mechanical.

[dpollo]

I had my 39 Overdrive for years and had intended to use it in a 37 Plymouth  ,  Recently, I gave it to someone else.

I have a 35 business coupe and I changed the rear drive ratio to 3.73 by using the housing out of a newer Plymouth.

It rolls along just fine.   I have R10s in my 50 and 51 and 52  1/2 ton.

[Richard Cope]

17 hours ago, Mike36 said:

I have a R6, no electrics on it. 100% mechanical.

 Appreciate all of your feedback, will keep you informed.

 

Regards, Richard

[rekbender]

I had a Mitchell OD (26% overdrive) in a Ford flathead powered roadster a while back.It did require a second lever to engage, kind of cool in hot rod. It got lots of questions.  It was synchronized and work perfectly, and had a speedo drive on the output shaft. I always used the clutch to go in and out. Not as slick as an R10, but you could split shift - I didn't. The Mitchell product seemed to be extremely well designed and built, but expensive. I don't know if parts are still available.

[Richard Cope]

Great photos, Mitchells still makes the unit, sounds like the one you had.  It is expensive $2,000 plus $200 for the floor shifter or $275 for a "T" handle that can be mounted under the dash and they estimate 12 weeks to receive after order is received.  If I go with it, installation would be rather basic - would remove the current driveshaft, mount the unit after the X member and have two short driveshafts made up with universal joints.  When you shifted the overdrive, was it a straight forward / backward motion with the floor shift  that could also be done with a T handle?  Do you recall if there was a position on the gear shift in which the overdrive was disconnected and you were only using the original transmission?  Do you recall how the unit was mounted, anticipate that I would have to install a brace across the X members to secure to,  however doesn't appear that your unit was fastened to heavy bracing?

Appreciate your help, just want to make sure that I understand the Mitchells unit. 

 

[rekbender]

17 hours ago, Richard Cope said:

Great photos, Mitchells still makes the unit, sounds like the one you had.  It is expensive $2,000 plus $200 for the floor shifter or $275 for a "T" handle that can be mounted under the dash and they estimate 12 weeks to receive after order is received.  If I go with it, installation would be rather basic - would remove the current driveshaft, mount the unit after the X member and have two short driveshafts made up with universal joints.  When you shifted the overdrive, was it a straight forward / backward motion with the floor shift  that could also be done with a T handle?  Do you recall if there was a position on the gear shift in which the overdrive was disconnected and you were only using the original transmission?  Do you recall how the unit was mounted, anticipate that I would have to install a brace across the X members to secure to,  however doesn't appear that your unit was fastened to heavy bracing?

Appreciate your help, just want to make sure that I understand the Mitchells unit. 

 

 

My lever was straight back and forth  - back against the seat was direct, forward was overdrive. The linkage was uncomplicated and could be easily fabricated if you wanted to save some money. Since mine was in a stock '32 Ford chassis, the OD unit was incorporated in the torque tube - no external brackets. I bought the car as an unfinished project and the OD was already installed in the tube. It was beautifully done, probably by Mitchell

[Lloyd]

Nice car!

Dont know anything about the Mitchell except it looks expensive. 

Just a comment on the R10. I have a 39 P8. Considered putting an R7 OD in it. The R7 and R10 have the same type shift linkage, takes one shifting arm for R, 1st and another for 2nd, 3rd. The 39 has a single shifting arm and a cable that allows for changing the shifting gate. The best way i could see to put an R7 or R10 OD was to swap steering columns with a later model that had the correct linkage.

 

An R6 OD on the other hand will drop right into a 39. Good luck finding one and if its less than $1000 its a deal. 

Have to shorten the driveshaft on any OD install so might as well look at a custom shaft using spicer style u-joints and get away from the Ball & Trunnion.