P15 Overdrive transmission

[greg g]

Even if it doesn't fit, it will probably appreciat in value if it won't work with your application, so body will want it.

[Loren]

Please, Please, Please install your Overdrive properly.

It's so easy to do. No toggle switches, please.

The large throttle switches are intended to be installed through the floor under the throttle pedal.

When the pedal is "floor boarded" it should trip the switch and that is why there are so any threads (adjustment).

This is the way they are intended to be installed on Ford products.

I prefer the smaller carburetor switch but sometimes you just don't have one so many people mount them to the linkage.

Mopar had a better idea mounting the switch in the engine compartment. That keeps the wiring where you can service it easily.

 

I said before they are available and not to over pay. I found one on the Sacramento.craigslist.org and on eBay.

I bought the one on eBay for $470 with a shipping cost of $213 (they are plenty heavy).

As I said before there are two guys offering Overdrives for around $2,000 which is way too much and 6 (now 7) have been sold for way less on the same site.

Do not over pay, it drives the price up for everyone else.

 

When you wire the relay, switch and solenoid for 6 volt remember the lower voltage requires heavier wire. Power to the relay and to the solenoid should be 10 gauge. The rest can be 14 gauge. It will work with all 14 gauge but it really is too light for reliable service.

 

The plans I have for the new Overdrive I just bought are to pull it apart and change the 2nd gear set to the 1940 ratio and to make sure nothing is broken or worn out. Since it is so easy to change the transmission in a Plymouth I will compare the two in the same car. If I like it, I'll change them both to the 1940 ratio.

 

In my 49 Coupe the car is so light your gear shifting is all done by 30 mph. It has 3.73 final drive gears and I intend to change the pumpkin to 3.54. As long as the engine can pull first gear its fine. Plymouth I believe figured on flat surfaces most drivers would start in second gear. That's why it is so low in all but the 1940. With speed limits of 55 mph that worked fine. 65-70 is another story however. Raising the final drive to 3.54 means you'll be using first gear from every stop. Raising second gear reinforces that but gives you a more even rpm drop between shifts. The Overdrive slows the engine speed another 30% at cruise quieting things down greatly. The engine now relies on its torque to maintain road speed. You'll be holding the throttle further open but at lower rpm thus saving fuel. The kick down will come into play more often with the 3.54 final drive but since it is automatic that doesn't add much work for the driver.

What was intended as a 2 speed transmission with a "Granny Gear Low" becomes a 4 speed  with these mods and it easily becomes a 65-70 mph car.

[Booger]

Its been over 50 years since I scored a r10 from a buddy ($75) and plugged it in to a p18 I had. Put the car up on the lube rack and bolted the OD tranny up from resting on my right shoulder. A simple hood release cable is all I used to engage the overdrive. 70 mph on 101 all day. Gas was .27c a gal you whippersnappers

[lucky13]

Sent the OP a message.  I have the R10 out of my 54 Savoy that I'm not gonna use anymore.  Located in the SF bay and don't mind meeting halfway.

[Bryan]

Which R10 ODs actually fit a D24 1948 Dodge?  When you look at Ebay there are R10 b R10k etc. Hooked up to Fords, Mercurys, etc..

[DJ194950]

R-10 G only matches original trans pattern. Must watch for input shaft length as they are varied if for a fluid drive equipped car or regular 3 speed.

 

This my past experience and reading other posts.

 

Their may be a R-11 variant heavy duty trans not sure what a correct letter after the R-11 would be. A recent post was on this forum about this trans was on the forum for Mopar use but they are very rare . I do know most R-11 (letter) DO not fit Mopar but other brands they are Reasonably avail. on E Bay.

 

DJ

[Loren]

14 hours ago, Bryan said:

Which R10 ODs actually fit a D24 1948 Dodge?  When you look at Ebay there are R10 b R10k etc. Hooked up to Fords, Mercurys, etc..

 

This is the beauty of the Plymouth Borg-Warner Automatic Overdrive. It uses a Plymouth transmission as its base.

You can swap your speedo gear from your old 3 speed and it will read just as it did before.

If the input shaft is wrong you can use the one from your old 3 speed as well.

The ID cast into the OD unit reads R10 G-1 on the two I have.

Because the base transmission is Plymouth/Dodge I am planning to swap the second gear and cluster for a 1940 version. (it is an alternate ratio)

A lot of the parts fit other car makes. B-W supplied them for 11 different cars.

Relays, switches, solenoids, control cables, etc. can be sourced from a Ford transmission specialist (Van Pelt Sales) at a much better price than other places.

Do not over pay for one! $1,100 to 1,200 is the typical going rate but I have bought them for under $500 and some folks say that's as high as you should pay.

[Young Ed]

2 hours ago, Loren said:

 

This is the beauty of the Plymouth Borg-Warner Automatic Overdrive. It uses a Plymouth transmission as its base.

You can swap your speedo gear from your old 3 speed and it will read just as it did before.

If the input shaft is wrong you can use the one from your old 3 speed as well.

The ID cast into the OD unit reads R10 G-1 on the two I have.

Because the base transmission is Plymouth/Dodge I am planning to swap the second gear and cluster for a 1940 version. (it is an alternate ratio)

A lot of the parts fit other car makes. B-W supplied them for 11 different cars.

Relays, switches, solenoids, control cables, etc. can be sourced from a Ford transmission specialist (Van Pelt Sales) at a much better price than other places.

Do not over pay for one! $1,100 to 1,200 is the typical going rate but I have bought them for under $500 and some folks say that's as high as you should pay.

Be careful on swapping input shafts. There are 2 types of synchros and they don't mix. Few years ago Dad and I were sitting at a car show. Another guy we knew comes up and starts talking about how he saw a really nice 51 dodge that had been swapped to OD. Dad goes oh who do you think did that? He and I had done it for the prior owner. His gyromatic was clunking so out it went and OD in.