[Chevindy]

Morning everyone, I have bought a 54 235 and want to swap out with the 6 cyl in my 1931. I would prefer to stay with the manual trans setup in the car for now. Can this be done?  Any help or suggestions are greatly appreciated

[sixball]

It is definitely doable. You will probably need a newer transmission to bolt to the 235. I believe Chevy went to what we think if as the standard transmission bolt pattern in '37 when they introduced the 216. If not shortly after so there are floor shift 3 speeds out there. It should be fairly easy to connect one of them to your stock rear end. Not sure about mounts and radiator clearance. This swap has been done.

[Chevindy]

Thank you for the information? I have measured the overall length of the engine including front pulley and fan and it?s very close to the same. I?m wondering now what the difference would be between my existing 31 trans the newer37 and up trans?  Could it be mounting bolt pattern? Perhaps input shaft and pilot diameter differences? Maybe a different # of splines on the clutch or maybe all of the above. I have a 49 truck transmission but it was out of a 3500 series so I expect the gear ratios are LOW.

[sixball]

Here is a poet I found. https://www.chevytalk.org/fusionbb/showtopic.php?tid/312826/
And a little here. https://www.jalopyjournal.com/forum/threads/1931-chevrolet-conversion.412723/

Yes the bolt pattern on the early transmissions are different. You might be able to re-drill the 235 bell housing or build an adapter. I don't know if  the spline is the same. You may have to do some searches and research but the information you need is out there. Keep us up on your progress. This kind of thing is interesting.

[Chevindy]

So as of today I can take the clutch fork from the 31 and cut it as well as cut the fork from the 39. Weld them together and I have that solved I can use my 31 clutch pedal?. I have bolted the bell housing from the 39 in and it?s fine. The bolt pattern and overall length of the transmission as well as the spline matches the 39. Now here is where I hit a wall? the throw out bearing on the 39 that came with the transmission has a sleeve over the input shaft and the 31 does not. That?s a problem even the bolt pattern is different on the retainer for the input shafts or I would just change it🤔

[sixball]

Can you use the two retainers to make one that works? If you are using the inner part of the '39 clutch release arm as well as the '39 trans & bell housing I don't understand why the retainer doesn't work. I think there is a lot of interchange with the bearing retainer between brands because transmission makers supplied several car brands. Finding that info may be tough.

[Chevindy]

 So the 39 retainer is one piece cast 5 bolt pattern and the 31 is 4 bolt. They both are cast from a non ferrous metal aluminum?? maybe and to complicate it further the profile on the inside of the retainer suggests that does in fact support the output bearing as I do not see a c clip holding that bearing in. So any replacement would need the same profile. It?s looking a lot more like a different transmission is the answer 🤔

[sixball]

OK, I'm confused. You have a '54 235, with a '39 bell housing bolted to it, and a '39 transmission.  Are you using the '54 flywheel, clutch, and pressure plate or the '39. Regardless the '39 throwout bearing should work withe the '39 trans. I don't see where any '31 parts would be needed. Maybe I'm just not getting it.

My '53 Chevy pickup came with a 216 & a column shift 3 speed. First I put a truck 4 speeding it. Later a 235 and finally a 270 GMC. I had a Saginaw 4 speed in it for a while. Now it has a T5. In all that swapping the T5 was the only thing that didn't just bolt up tranny to engine wise. There are a long & short throwout bearing. I don't remember which I have. 

[Chevindy]

It?s the truck transmission that I have but I thought it would be some crazy low gear? It has a reverse lever on it and it?s quite a bit larger with the passenger 31 I have. It came bolted up to the 235 with attaching clutch pressure plate and linkage and I can see it?s physically larger than the 31 trans so with that torque tube being pretty a set length to work with I figured the low gear and bigger size ruled it the truck transmission?
Part number on the case is 590474 and date is J150 and case cover is 590611
Thoughts? and I do appreciate your time for responding to my questions 😎

[Essex_29]

I don't know the ratios for your truck transmission, but in my  case, a '67 Chevrolet C30, the
transmission would probably have worked decently in a car. It was four speed, though, and
you would have used it as a three speed as the first gear was extremely short. It might be,
the truck transmission of yours has very wide spread on the gears, but high gear will always
 be 1:1, truck or car, the revs at speed will be the same  regardless.

[sixball]

Some of the truck transmissions had both compound low (Granny Gear) and a 5th over (over drive). But this a large and very heavy. I can't think of any GM trannys that had a separate reverse lever. Is there a PTO init bolted to the lower side. Most of the truck boxes had a plate on tach side with 4 ir maybe 6 bolts so a power take off unit could added to run other equipment ( winches, hydraulic pumps, etc). See if you can pick your trans from these and look it up for more info.

I agree with Essex that most of these old transmissions have a 1to1 high gear unless they have a 4th or 5th over. Almost any of the 3,4 and some 5 and more speeds will bolt to your bell housing. Most will match your clutch splines and use a throwout bearing that will fit your fork. It may take some searching. The Chevy pattern Borg Warner T5 may need a different clutch plate. Also a bit cut off retainer snout or an adapter/spacer between the bell housing & trans. 3/8" I think. The issue then is hooking them to the closed driveline. There was an outfit (Patricks in Arizona) that made a closed driveline adapter for the Saginaw 3 & 4 speeds but they are long gone. That is why so many go to open driveline and better juice brakes. On one truck 4 speed I put in a '49 Chevy pickup I was able to use the rear piece from a closed drive trans that just bolted to the newer open driveline trans. That was at least 60 years ago when these parts were everywhere and cheap.

[Chevindy]

Well thanks for the input? the reverse lever I?m referring to is actually directly connected to the shifter handle and consists of a simple finger pull up to access reverse. So the new plan is to purchase a 1940-54 3sp bearing retainer and swap out the bearing retainer on the 31. The new retainer has the collar for the release bearing to slide on. I talked personally to The Filling Station and a helpful employee put an example of the 31 bearing retainer and the 40-54 in his hands and confirmed with minor modifications it could be swapped. I just don?t have the money or time to go for a full on swap with juice brakes and a more modern driveline (even though it would be preferable). Also residing in Canada our laws on safety certificates to license the vehicles are tricky and harder to navigate

[sixball]

That sounds like the easiest and least expensive way to go. Just bolt it up to your stock trans & rear end and take it easy. Good to know the retainers will swap with just a little work. be surety keep us up on how it is going. Some pictures of the car and the swap would be nice. The Filling Station is one of the last of the places where you can get that kind of help. Lots of good parts too.