Transmission identification 35991

[General23cmp]

I have a 1940 Plymouth truck, but I believe the transmission has been swapped. The transmission case has a casting of 35991 on it, and the passenger side has a large X shape cast into it near the top. PTO covers on both sides. Any help would be appreciated. Please see pictures. There is another casting on the passenger side, but it is difficult to make out. It may be D14-1, B14-1, CB14-1 or something like that. Pardon the mess. I am cleaning. 

[Young Ed]

Looks like a 4 spd which was an available option. Dad's 40 Plymouth also had a 4spd but when we rebuilt it we swapped it to a 3spd and put the 4spd into the 46 dodge yard truck. 

[General23cmp]

Yes, 4 speed. I’m just having trouble identifying what version it technically is called. I have seen similar ones called “early transmissions” and “up to” transmissions, but would like to nail down the true model/type. A search for that casting only gave another forum’s post with a guy asking the same thing. 

[Robert Harrison]

You should be a member of the 39-47dodge truck group.  This is a good group here really a sister group but not the most dedicated to the 39-47 Job rated trucks. Originally on Yahoo but when Yahoo went away they went to io.  There is a lot of info on the files section.  I recently posted this stuff but I have a lot more on this subject as I researched it deeply.  I belive you have an origainal for the period New Process 420 non syncro 4 speed.  It looks like the right one for the year.  This is a good thing as there are many parts still available for it some through military sources.  The later model made about 1950 has some syncro.  You can identify them by the type of drain plug.  I am going to send you the files that match your request closest but there is maintence stuff and I did a sleave repair file recently as well that you would want to have.  Was hard to dig all this up in 2024 had a dickens of a time finding the correct torque rating for the drive shaft pinion.

4 speed 420 transmission types.doc 4 speed transmission Yolk repair and Instalation.doc

[General23cmp]

Thanks. This is great. I always thought “new process” started in the 1950s. 

[General23cmp]

You mention it being right for the year. Was there a New Process 420 in 1940? I’m having trouble finding a rebuild kit that states anything that old in the year range. Would it have another name/model called out?

[Young Ed]

I got out my 2 parts books and they both just call it a 4spd. I didn't find any mention of who made it. They may not have wanted to call out that it was from an outside vendor 

[lostviking]

This thread seems to be talking about your transmission. https://forums.g503.com/viewtopic.php?t=261426

[General23cmp]

Yes, I saw it. Thanks. That’s why my first post had that last sentence. It didn’t seem to get firm resolution. 

[wallytoo]

i can't help with identifying your transmission, but new process transmissions were in dodge trucks in the 40s.  the oem 4-speed in my '48 1.5-ton is an NP non-synchro.