Sm420 u joints

[jeffbcn]

Anyone know where I can find u joints for a sm420 sincromesh transmission?

[mongocanfly]

I've gotten all my u-joints from oriellys..you could also go to rockauto if you know the numbers..

[jeffbcn]

Not only do I need u joints but I also need slip yoke.

[1project2many]

Spicer U-joints are among the best I've used. Spicer driveline dealers can get most of the items. We use Gilbert's Driveline in Manchester NH.

[mr48chev]

Ok what is the trans in and is it open or closed drive? It speeds things up mega times if one puts the full info on what he or she is working on in the question. Year, model and what not that we might need.

A regular U joint for an open drive drive shaft can be found at O'Reilly's or at Napa 95% of the time but you might have to wait until the next freight truck from the warehouse for odd ones. One for a closed drive might call for a bit more effort.
Open drive yoke you can probably get at a local driveshaft shop Closed it is specialty house or used.

[jeffbcn]

47 chevy Thriftmaster with 235 from 1962. 4 speed on floor. I was told that the 47 had the clutch pedal bracket on the bell housing. This one has it on the frame so I was told 48 or later transmission. I assume it is a sm420 based on research. It has a torque tube not an open driveshaft. I need the yoke and u joints.
Anyone who has one of these AD"s know you almost have to be an automotive archeologist to figure out what is original and what has been swapped out. I'm learning as I go.

[dwcsr]

Originally Posted by jeffbcn

47 chevy Thriftmaster with 235 from 1962. 4 speed on floor. I was told that the 47 had the clutch pedal bracket on the bell housing.

No in 47 there were two body styles, 47.2 was just like the 48. Do you have a small lever on your shifter that goes to the transmission cover? If yes its a 47. 48 up did not have that , 48 up had a syncro trans, 47 was a non syncro.

I assume it is a sm420 based on research. It has a torque tube not an open driveshaft. I need the yoke and u joints.

Chevs of the 40, Jim Carter and Filling Station should have those parts.

[cooperhw]

I am pretty sure they are 100% legal in Colorado, Oregon, Washington, and soon in California for recreational use. Many other states for medicinal purposes only.

[jeffbcn]

Cab plate shows made in November 1947. No small lever on shifter. No emergency brake in now bit evidence of pedal mount on bottom of dashboard near drivers door.

[jeffbcn]

Called Jim Carter, filling station and chevy of the 40"s no dove nothing.

[pvienneau]

Hi Jeff, I worked on the same thing for my 49 standard 3100. Why do you need these parts? Did you lose or never have the originals?

[pvienneau]

Go to page 58 of the build in my signature and see if this is what you need?

[jeffbcn]

Sure looks like it. Transmission started vibrating. I had it pulled and u joints and yoke exploded.

[mr48chev]

Originally Posted by jeffbcn

Cab plate shows made in November 1947. No small lever on shifter. No emergency brake in now bit evidence of pedal mount on bottom of dashboard near drivers door.

That should be the 48 style cab. 47 had the emergency brake handle beside the shifter on half and three quarter tons.

47 had the small older style bolt pattern on the trans to bellhousing and 48 had the wider bolt pattern that was used with most separate trans and bellhousing setups on Chevys up through the years.
Somewhere on this post is a photo of an adapter. Don't pay attention to the holes around the center hole they are for the bearing retainer. What you are looking at is the difference between the early bolt pattern (closer together) and the later 48 and up bolt pattern. That is the quick way to tell the difference between 47 and 48 trans.

[mr48chev]

You should be able to check the serial number on the door post tag against the lists to see what year model it says it is there. Still a few states insisted on titling new cars and trucks as the year they were sold rather than the actual factory year model up into the mid 50's.

This is one of the easier to follow pages to tell the difference between years by vin.

https://www.chevytrucks.org/resources/ad_vin_id.htm If it is an e something it is 47 if it is an F something it is a 48

[jeffbcn]

Thank you all that tried to help me. Once again I have gained a deeper understanding and appreciation for these Advanced Design Trucks and their owners. Especially those who attempt to keep them stock.
I know that back when these were built there was not the documentation that we have today. While many parts are reproduced and readily available today, many are not. Some don't appear in any catalog but only in the memories of a few old timers. Alas, they are a dying breed.
I called all over the country looking for parts. None of the well known suppliers could help me. Nothing was listed in their inventories. Luckily I found a few people who knew what I needed and were willing to scrounge around in their obsolete inventory to find them.
It looks like I will finally get it repaired but not completely rebuilt. My 3rd gear syncro will will have to wait. Nobody seems to have those but at least I will be able to get it back on the road and enjoy it!

[mr48chev]

Check with these guys. https://www.novak-adapt.com/catalog/...ts/sm420-parts They sell a complete kit but show that the third gear synchronizer cone is in the kit so they probably will sell it separate. Looking again it says that they are out of the 3rd /4th gear syncro but intend to manufacture them soon. I'd be checking with them on it.
They are also loaded with info on those transmissions and any swap trans setup.

The SM420 or versions of it is still real popular with the early Jeep bunch for their crawlers.

[mr48chev]

HERE!! scroll down the page the one for the pickup the top one if for trucks with a PTO setup. http://www.americanpowertrainwarehou...pto-wt250-14a/

They say supply is limited but give it a try. the also show other pieces for the trans including a gasket set further down the page.

[jeffbcn]

Novack could not help me. Thanks for the other info.

[BJC679]

Jeff,is this 3800 or 3900 series or what?I have some old books at the shop and I will try to run some numbers for you .How many ujoints does it have and does it have a center bearing assembly? Bobby

[jeffbcn]

3100 series, half ton. I believe half of the yoke is inside the transmission and the other half slips onto the torque tube. I needed both halves, the u joints itself and attachment hardware.

My Driveline people have since told me they found those parts in their obsolete inventory . Hopefully I'll have it back in a couple days.