The Stovebolt Site Forums The Shop Area General Truck Talk 46 1/2 ton U-Joint questions..

I busted my cobbled together u-joint on the '46 a few weeks back, and have been looking for a full replacement, and thought I found one a week ago in what I was told was a '41 thru '46 truck.. it was just the running gear and chassis sitting on the ground, so I had no way to confirm the year, but it was a torque tube setup.

I pulled it apart, and while the joint itself looked different than mine, I thought hey, it looks about right, i'll give it a try.

Turns out on my original part, the tranny side, the do-dad has 10 splines.. but on the side that slides into the driveshaft it has lots more splines, and alot smaller.

The joint I pulled out of the donor vehicle had 10 splines on each side.

Recently, I ran across a fellow in the swap meet section with '46 parts for sale, so I asked him about the joint.. a few days later, he sent me a pic.. that looked just like the joint I pulled from the donor vehicle.. an eMail later, he confirmed that his has 10 splines on both

So my question is.. did they use two different kinds of joints in '46? Or maybe the part I got (and the one this swap meet guy has) are from a 3/4 ton? Did they use torque tube setups in 3/4 tons in '46?

Or maybe somebody did something goofy with MY truck in the past, and it's ME that has the wrong joint?

I wanna get this figured out, because if I end up having to bite the bullet and buy a brand new joint, I don't wanna end up with the wrong thing.

So I guess what i'm asking is, is 10 large splines on the part that connects to the transmission and more than 10 much smaller splines on the part the slides into the driveshaft sound right for a '46 1/2 ton u-joint? What would 10 large splines on both sides of the u-joint be for?

My gearbox to the engine has 10 splines that fit into the intermediate torque shaft, from there to the differential are X universal joints connected by a short tube.
There are long shaft differentials that run from the diff to the gearbox, these have the bell housing at the forward end, can't comment on what way they fit together.

My '46 3/4 ton does not have a torque tube.

It does have the original tranny, and the original rear end, so I'm inclined to think that it's still in its original configuration.

Of course, anything's possible. Especially knowing my grandpa.

Perhaps your driveshaft had been repaired previously with a part that was from an earlier or a later model.

My 46 1/2 ton has the "torque tube" going directly from the rear differential straight to the transmission.. nothing between them.. and the "torque shaft" connects to the tranny with a U-Joint thing.

Te donor vehicle had a identical tranny, going to a 'baby' driveshaft torque tube thing, that mated up with the torque shaft that went to the differential.

I took both joints, hoping that I could get one of them to work, but neither of the joints have the "fine spline" on the torque shaft end.

So perhaps the part I pulled, and the part the guy from the swap meet section has, is actually a u-joint from a '42 3/4 ton?

Here's another question.. is there a difference in u-joints between the 1/2 ton 4 speed tranny and the 1/2 3 speed?

Seems like both Jim Carter and Chevy Of the 40's only lists a u-joint for the 1/2 ton 3 speed.

I recently swapped out my rearend for an open driveline setup. In the old setup, the yoke coming out of my original 4 spd. tranny had 10 splines then the u-joint then another sliding yoke with 17 splines that went into the original torque tube. If you want pics of that setup I can send it to you. john.

Sounds like what you had in your original setup is what I have.. I havent counted the splines in the 'sliding yoke' that goes into the torque tube, but they're alot smaller splines than the tranny side, and way more than 10 of 'em.

I was checking out Chevy Of The \'40\'s u-joint selection and they don't list anything for the 4 speed tranny.. just the 3 speed.. so i'm not even sure what they have for a '46 1/2 ton will work for me.. and nothing on that page looks likee joint I pulled out of that truck.

Eventually i'd like to swap out the rear and go with a t5.. but for now, i'd be happy with just putting it back together stock.. provided I can find the right part!

Check this page for '46 truck u-joint yoke and prop shaft spline info.

Sounds like you need a '40-'46 1/2-ton, 4-speed, u-joint.

If i'm reading that right, all 3100 and 3600 (1/2 and 3/4 ton trucks) have 10 splines on the tranny side, and on the 3100 the rear of the joint has 17 splines, and the 3/4 ton has 10.

Since there dosen't appear to be any mention of 3 or 4 speed, I guess I can assume that the same joint was used in both the 3 speed and 4 speed trannys.

I absolutely know for sure the '46 2 ton dosen't use torque tube crap.. this chart dosen't seem to have any mention of which models used torque tube and which didn't.. so now i'll just have to narrow down what year(s) the part I have will fit.. maybe I can find somebody who needs it.

Fumblin - I don't remember how many splines my 46 3spd had but I do know that the u-joint is different from the 4 spd. so when you are lookin for a replacement make sure you have one for the trans you have.

George

The 3- and 4-speed output shafts both have 10 splines, but the splines are shaped and sized differently and the shafts are different diameters. Look again at the trans main shaft & front u-joint front yoke info in the chart. Model 1 is the 3-speed, and model 6 is the 4-speed (RPO on 3100 and 3600).

The 3100 is the only model with the full torque tube. I think the front shaft on the 3600 is enclosed like on the AD's. At least it is on the '41 according to the \'41 shop manual.

I can take a picture of my 3600 tonight when I get home if you like.

Xram.. I didn't see a '6' in the Propeller shaft section, so I just assumed that they were the same, but apparently I was looking at it all wrong.

Jim Carter and Chev of the 40's only lists u-joints for the 3speed.. what's up with that? Were the 4 sppeds some kind of rare thing in a 1/2 ton?

Anybody got a source for them?

Fumblin46,

Try Bruce Bugay. I got a complete nos uni assembly from him a few months ago. His email is [email protected]

Good guy to deal with. He has a lot of stuff for the 41-46 models.

All the best

Bob

I shot him an eMail.. is he here in the states?

Yep Frank. He's in the US.

Bob