Saving from scrap

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JimC
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Re: Saving from scrap

Post by JimC »

I didn't want to modify my frame or bodywork.
onemanarmy
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Re: Saving from scrap

Post by onemanarmy »

I'm not planning on changing the frame or bodywork either.

No PTO on this truck.

So to mate my military factory trans to a 318 or 360, I will need to source a civilian M37 trans and swap some parts? Again, why can't the civilian trans just be used? I understand the linkages part for the NP435, and are the linkages different between the civi and military NP420? if so, that may not be ideal.

I think the exhaust routing is the least of my worries. Ha.
1958 M37 saved from the scrap heap....in parts
JimC
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Re: Saving from scrap

Post by JimC »

Why will you need a civilian M37 transmission? (I've owned these trucks for over 50 years, and I didn't realize there was such a thing). There are however, two versions of the M37 transmission. You can tell them apart by the shifter housing. For me, the transmission was the least of my worries. I used the military M37 transmission with a civilian bell housing and clutch. Routing the dual exhausts was a real pain.
onemanarmy
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Re: Saving from scrap

Post by onemanarmy »

I must have read your previous posts wrong.

I was interpreting them as needing some Civilian M37 parts to mate the 318 and the stock M37 trans.

So, to clarify, I source a 318/360 out of a Dudge truck with a manual trans, and the stock M37 trans will bolt up? Any adapters/parts/funky setups/particular years of engine that wll be needed to make that happen? I've got a line on a truck and want to be sure.

Thanks for the help.
1958 M37 saved from the scrap heap....in parts
JimC
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Re: Saving from scrap

Post by JimC »

You will need the longer and correct length civilian pilotshaft and the longer pilotshaft housing that match the V8 bell housing and clutch (see photo below). They go in the front of the military transmission replacing the short military pilotshaft and pilotshaft housing. All else remains stock. I must be misunderstanding something as well, because I did the swap in 3 days over 50 years ago. I didn't notice anything at all difficult about the swap at the time except for clearancing the exhausts and exhaust manifolds where they exited the engine compartment.. Perhaps I did it wrong? I only ran it for a couple of years before I swapped the 318 out for a bb chevy. I averaged 13 mpg with the 318 and 11 mpg with the bb. Maybe it is difficult, and I just succeeded out of stupidity and luck. I quote below, someone else who did the same swap about 30 years after I did. Note also, the two different pilot shafts and housings in the attached photo below. From falliable memory, you want the bellhousing, flywheel, pressure plate, throwout bearing, clutch (Borg & Beck ?), pilot shaft, and pilotshaft housing from a W200 1961-1968 V8 (don't hold me to that - check it out for yourself - I used a 1962 - you can also buy the parts individually). I had a hard time finding a suitable set of exhaust manifolds with the outlets where I wanted them to be. Took several hours of junkyard prowling for that. I remember all of this as being dirt simple. BTW, have you considered a 383 instead of the 360?

"The early and late M37 transmissions will interchange without any modifications. The NP420 used in the M37 is the B series or later transmission. There is also the civilian NP420 transmission. The input shafts used on these transmissions are of different lengths. And you will find find different input shafts on the civilian 420's. Also the bearing retainer or throw out bearing sleeve will have a different outer diameter. The good news is that the internals between the two transmissions are interchangeable. A civilian NP420's input shaft and retainer will bolt into a M37 NP420. You will find the mounting ears between the two 420's are different. One hole on the M37 will line up on the civilian bellhousings. Two holes on the M37 420 will have to be ground or milled to align with the civilian bellhousing as they are close but not close enough and the fourth will need a new hole just next to the original, This ear is wide enough to allow a whole separate hole to be drilled. Civilian 420's are getting scarce. Internals between the 420's and the 435's are not interchangeable at all. 

Making the modifications for an M37 420 to a civilian bellhousing is fairly easy. The downside is the clearance between the PTO and the bellhousing. The bellhousing will have to slightly ground in noncritical areas to allow the marriage. It is a reliable and fairly simple modification to drop a Mopar V8 into a M37/M43 and it is really rugged".
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