VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 What Transmission for 37 Chevrolet Truck

A warm summer greeting to all of you from The Land Of The Midnight Sun. - Finland


I thought Id ask you professionals about a replacement transmission for our 37 1/2 Ton Chevrolet Truck. I have purchased a new and totally manufacturer rebuilt 235 engine for this ol timer. However I need to find a nice transmission for it that also would be easy for my wife to use.The truck now has a 4 speed. What suggestions would you have and do you know of a transmission that would bolt on fairly easily? Can I purchase one new possibly?

A sincere thank you for your assistance.

Best wishes
Classic Finn

The 3 speed from a 1937-39 truck will bolt right in.That is what most of the 1/2 ton trucks were equipped with.

MUCH easier to 'deal with' than the four speed. Suggest you 'convert' to the 3 speed. As Gene indiates, it bolts right up.

Gene: What about a Powerglide.....

Or, a 54 'hydramatic' like in the GMC pick-ups????

Bill.

By what I have been told to change from 4 speed to 3 speed transmission will require rear change as the enclosed driveshafts are different lengths. I have not physically compared them yet, the 3 speed rear axle rotted away in my 38 and I obtained a 39 with 4 speed trans as a donor. At this point I was informed of the difference. My guess is that the trans are different lengths.
Tony

The drive shaft/torque tube are of the same length...the U joint is different.The 3 and 4 speed were designed to be easily interchanged if needed.The length of both transmissions are the same.

Chevgene:
Old Blue ('37 1/2 ton) has a 4 speed and I'm thinking about replacing it with a 3 speed I got when I bought the truck. Is there a difference between the car and truck version of the 3 speed? Are there numbers I can check against a parts book list? Is there a way to run a preliminary test on the tranny without installing it. It would be a hassle to install it and then discover it was all a waste of effort.
Thanks, 37Blue

The truck case/transmission is longer.This was done to match the length of the 4 speed for ease of exchange.The car case casting # is 590822 and truck is 590874.The internal parts are the same except the truck gears had a better heat treating process for greater durability AND the truck mainshaft (rear shaft) is 9 43/64" long and the car is 7 17/32" long.

The 4 speed also used a special bracket for mounting the master cylinder and the bracket was not required for the 3 speed.

The only way to "test" a 68 year old transmission would be to disassemble it and check for wear.Most of these units had a long, hard life and will require some work.

To All of you Id like to say thank you for your advice and information.. Its helpful indeed. can anyone tell me as to where I may find a 3 speed and what is the going price for this?

Can I go with a model later than 39 without changing the rearend or Enclosed Driveline? You mention Powerglide or A Hydramatic ?

Classic Finn

I think that you can use a 1941-47 pickup 3-speed, but it requires a special u-joint. Someone else may have some comments on this transplant

I have one of those U-Joints in my building.

So, how about it?? I'm curious myself. Can "Classic Finn" use an automatic in his '37 1/2 ton??

If not, can a later model, '41-'47 or '48-'55 for instance, P.U. be converted from a 4 spd or 3 spd to a PG or GMC hydramatic??

And, what would be involved in changing to the automatic transmission??

Bill.

Converting to a 1953-54 PowerGlide presents a number of problems:

1. 1937 engines only have a 4 bolt flywheel
2. Length on the torque tube and prop shaft
would have to be adjusted to fit the chassis.
3. A 1953-54 235 with a cast iron PowergGlide
would be the best that you could come up with
and it is a lot of pain for the gain.

Any of the GMC/Chevrolet truck hydramatics from 1953-54 would present about the same problems

Thanks to all for the info. As always these info exchanges are great. Just one of several reasons to join VCCA.
37Blue

Hey Classic Finn.....

Warren has posted a pretty negative reply indicating there are lots of hassles to the idea you and I thought might be pretty good.....

His post is just above (back two posts from) this one.... also on July 12.

Thanks for the info WD. It's always better to know what's up ahead of time!!

Bill.

I put a 53 PG in a 41 half ton Panel. It required moving the rear axle back about 2.5".
FYI: 37 passenger 3 speed are about 9" long. 1932 - 1947 truck trans are around 12" long. 1948 - 54 trans are 14.5" long. U-joints and splines are different but can be interchanged.

Lou,

It's always nice when you 'show up' when there's a truck 'question'.....

That must have been a 'kick' to have a PG in your '41 1/2 ton panel!!!

How did the rear wheels 'look' in the wheel well opening after you moved the rear axle back "about 2.5 inches." ???

Bill.

Last evening I read a 1937 service bulletin with an article on 3 speed trannys. It provides a seemingly detailed explanation of how to take one apart and replace worn parts. It refers to and has photographs of several special tools; a thin open end wrench, odd shaped hook-like pliers and a transmission stand. Does anyone know anything about these tools and where a guy could buy, rent or otherwise use them?
Thanks, 37Blue

Thank you ever so much for the "Informational Package". Its great to get so many replies wether
being positive or negative..

Thats what this is all about...especially when Im
working pretty much alone on this project but slowly and surely I hope to overcome this. Especially when you great folks are here.. I,ll let you know what I come up with.

Again thanks to All
A warm summer greeting to you.
Classic Finn