Jump to content

1940 Plymouth p10 rear differential id


1940 p10

Recommended Posts

Hello all,

This is my first post on this site. 

I just purchased a 1940 plymouth p10 4 door sedan, and I have a couple questions.

I am having a hard time finding the name of the stock rear differential? I have found every part, shop manuals, etc... But cannot find the model or name?

And what is the general perception of these diff's? The guy I bought the car from has a junked 77 nova that I could buy the rear axle from, but I want to know more about the stock unit before i assume i need to go later model. 

Thank you very much to everyone in advance ,

Brad

Link to comment
Share on other sites

if you looking for a magical sounding name like 8 3/4 or other such as found in the later muscle mopars  you are going to be disappointed.  While these rear axles are built similar to the early 8 3/4 they do not share the famed history.   Are they bad, I think you need to look at the very history of the car...the car is here it has the factory rear gear...testament enough for a stock running vehicle.  Now your post may be a bit incomplete and your end run is the all out rodding of the car with engine transplant and other drive train mods and asking if this axle will handle the increase in HP and possible intended abuse during operation.  Bur for stock purposes...you will be more than fine....perhaps a bit more information to what you are intending with the car will draw comments more tailored to your original question about the rear gear.

  • Like 1
Link to comment
Share on other sites

Thank for quick reply. I plan to hot rod it a bit with a V8 and a th350 trans. I have access to a driving 77 nova with a straight 6 and auto trans (i plan to use this trans, but different v8).  So im wondering if the stock rear end in the p10 should be replaced giving my intentions to hot rod it a bit, and put some miles on it? Or should i plan on swapping out the diff with the nova donor? The track width is near identical. I understand the pearches will have to be relocated. Thanks again. 

Link to comment
Share on other sites

so...we part way there...this V8..stock or modified and your intended driving for the beast.....crusiser of rip snorting around dogging the beast.  As for the rear axle your call...any and all are an easy exchange.  Do keep in mind that the front wheel pattern will be different from stock and somehow I do not see an issue here either as I sorta think that a Nova subframe is also in the works...

Link to comment
Share on other sites

Lightly modified sbc. Something to romp on a bit around town and do the occasional short road trip. I have been considering the sub frame swap. Sounds like I should buy the nova and do some modernizing. Thanks again for your input. Very valuable feedback.  

Link to comment
Share on other sites

If you are considering the Nova subframe which is by all account your call...I would however like to point out that you look at a few that have been built in this manner and inspect the very profile of the front of the car after the swap was complete  not withholding the very manner of connecting..  There are better subframes options out there...but then again, there is really little need to go to that extreme either as the stock setup can be modified with low cost and not super invasive at the same time.   I would ask you to study some of the options before playing follow the leader. 

Link to comment
Share on other sites

The differential used from 37 to 48 in most all Chrysler products is a very durable and trouble free unit. I have seen them stand up to much abuse and even a few V 8 swaps.  If you are changing your engine  and trans  the limitation the stock rear end imposes is the lack of a parking brake..

As PA says above, have a real good look at the stock front .suspension .    These were nice handling cars when equipped with a sway bar as most P 10s were.

Link to comment
Share on other sites

Will do. Good to know. A "not super invasive" solution is good. I'm not sure I would outsource another sub frame at this point. The nova just happen to be a really good deal, and I would rather not spend the money if the factory foundation is solid. 

An I'm not too worried about the lack of parking brake. I was concerned the factory rear axle would be hard to find replacement parts for, but after doing some quick research, it seems there are things like wheel bearings, and seals available through my local parts stores.

You guys are giving me great info.

Link to comment
Share on other sites

I have had my 1940 Oz built Dodge sedan since 1971, its had a 318 Poly V8 since 1973, 4 wheel discs, rack & pinion, etc........my advice is to upgrade to a set of disc brakes on the front stub axles, a relocated shock absorber upper mount kit, late model diff WITH an emergency brake included and say a 318/360 mopar & auto.......all this stuff will more or less bolt in and will not result in a bastardised chassis/front clip swap that will REDUCE the actual value of the car........these improvements will allow for a nice cruiser that mopar owners will give a knowing nod to and even tho' its a hotrod the restorers will still give you credit for thinking and doing outside the box.................the stock diff rear axle will hold up if in good condition and you don't put the boot in but theres also the issue of still using the stock uni joints which would be the 1st suspect weak link then............if you are gunna do it then do it right the 1st time.................my Oz 2 cents worth..................regards...........Andy Douglas.   

  • Like 1
Link to comment
Share on other sites

Though I am not a huge advocate of a "clip" there are good reasons to install a modern suspension.  The original suspension, though very good, lacks certain characteristics that a more modern independent suspension would give like a good roll center and anti-dive traits that are not present on the factory suspension.  The factory stuff's biggest limitation is its a king pin suspension but it's good enough for a lot of people.  

I installed a GM clip in my 47 and I had to purchase Fatman narrowed control arms to get the track width in check.  Probably cost the same as a Mustang II in the end.  The notion that a CORRECTLY installed clip will reduce the value is simply not true.  Kind of like saying your 40 Plymouth is worth more as a stocker than a rod, which is also not true.  But there are a lot of butcher jobs out there that would bring down the value though.

I believe the rear axle was used behind many V8 mopars including Gen 1 HEMI's, so it should be plenty strong but you will probably rip it out and replace it out of frustration the first time you attempt to remove the drums to do a brake job. That and the lack of a parking brake....  Also, modern drum brakes are light years ahead of the ones on your stock rear axle and no unobtainable tools required to sent them up correctly, just a brake spoon.  Keeping the same bolt pattern is only a concern if you are using stock wheels.  Multi patters wheels are the norm with most aftermarket rim suppliers so don't worry about it.

Link to comment
Share on other sites

Wow. This is all really good info. And I really appreciate the different perspectives on this. You have all given me a lot to think about. Thanks again to everyone. I'm gonna look into putting the sbc aside and picking up a local guy who is selling a 318 / 727 combo. I've done so much with ford and chevy, why not dive in with some cool mopar stuff and learn something new. It would be cool to keep it all Mopar, I think I'm gonna add the v8 and auto, and then keep my eye out for a later model mopar rear end. I just got done working on a 49 gmc truck, and the one thing that killed me was trying to find parts and pieces for a rare eaton ho 72 rear end. I ended up getting a late model dana 70 (it's a 1 ton) and haven't looked back. And I plan on driving the plymouth, not looking at it, so serviceability is key.

 

I'll keep everyone updated with the project. I tend to get a little "obsessed" once I get a new project, so there should be lots to report.

 

Thanks again to everyone on the site for the thoughtful replies.

Brad

Link to comment
Share on other sites

I had good luck with a Cherokee rear end.  The 8.25".  Its about the same width and same bolt pattern.  They are pretty easy to find.  Avoid the Dana 35 out of the Cherokees.

Link to comment
Share on other sites

  • 7 months later...
On 27.12.2016 at 4:35 AM, Bmartin said:

I had good luck with a Cherokee rear end.  The 8.25".  Its about the same width and same bolt pattern.  They are pretty easy to find.  Avoid the Dana 35 out of the Cherokees.

Hi - just checking - using the Cherokee rear end would require a complete axle change or can I just change the rear pumpkin incl. the rear end 3rd member with gears?

thanks

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.

Guest
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