The Stovebolt Site Forums The Shop Area Driveline 47 3/4ton tranny swap

Hey guys, thanks for welcoming me to the site! I have a 1947 3/4 ton chevy pu. The 4speed has been removed and it has a 3speed in its place. Anyway the 3speed started giving me some problems and jumping out of 2nd gear. I cant seem to find anyone that will commit to rebuilding it, they all give me the runaround. The casting # is 591195. I looked that up an it says its a commercial 3speed made from 41-47. I would love to have it rebuilt, but it looks like Im gonna have to go with a different tranny. Can anyone tell me what the easiest tranny swap would be without alot of FAB work under the truck???
My next question is if i put a 373 rearend in this truck will I have enough of a first gear or should i shoot for a 410 rearend. The truck still has the original 473 rearend in it and top speed is around 45-50. I would love to get the old truck up around 60 just to keep from getting run over out there.
Well thanks for reading the post and any help or advice will be greatly, greatly appreciated!
Thanks again and have a great day!

Now will be a good time to think about a T-5 conversion. Are you still running a 216 engine?

My 53 3/4 ton now has 4:11 rear end gears and wow what a difference it made in all around driving. The 53 has the carrier bearing then to the open drive line, guess your truck would be similar. This may make swapping the trans a bit of a job vs. a bolt in but the overdrive trany would be a huge plus.

The motor was rebuilt in 1997 and it was made into a 235. The drive shaft is like your 53, so I'm gonna have to take some measurements and see what I need to do to make it work. I bought a rear end out of a 63 3/4 ton,I think it has 4.11 gears. I'm gonna swap those out and then go for the T5. I just need to find out what its gonna take with my style of drive shaft. If any one has made this swap please let me know. I'm very interested. Thanks again all!

I haven't worked with the numbers but I would guess that if you install a T-5, you won't need to change your rearend ratio.

Do you mean that they installed a 235?

I understand going for a higher speed rear end, but...
The 1947 3 speed parts are readily available, you may need to talk to a different trany shop, check eBay, or PM me.
A T5 is a good swap but would require a 1948-53 bellhousing to get the right bolt pattern.

A stock '63 3/4 ton rear will have 4.56 gears. The 4.11 3/4 ton rearend wasn't offered until '68.

It may be possible to remove the carrier bearing in the driveshaft and go with a 1 piece driveshaft. The carrier bearing crossmember would also have to be removed or re-engineered as a driveshaft loop.

Ok my 47 has been in the body shop for a year now so I'm just now fixing my low rear end and tranny problem. Anyway a mechanic friend of mine gave me a 2 speed powerglide out of a 69 camero and swears it will get me up to 65/70 w/o changing the rear diff. Does anybody have any experience with that and do you know if I will get any more of a top end?

What will be your rear-end ratio?

Will you need an adapter to mount that Powerglide to your engine?
Is your engine the 235 your refer-to above (what year 216/235 is that engine - what is the engine serial number)?

Do you know if the 1969 Powerglide is a "standard" Powerglide or a "Torque Drive" Powerglide?

I believe ALL Powerglide transmissions are 1:1 final gear, so whatever rpm you run now to get to 70 mph with your stock transmission will be the same as with the Powerglide.

Mike B