Chevy used the short tail TH400 in many different applications. Some had a slip yoke, some had a bolt in yoke. The bolt in yoke was used mostly on trucks, 3/4 ton and larger, that had a slip yoke in the center of the two piece driveshaft. The cars and trucks that used a one piece driveshaft had the normal slip yoke in the transmission. Half ton long bed trucks usually had a slip yoke in the transmission, with a carrier bearing in the middle of the driveshaft. And then there was the Vette...they had a slip yoke at the transmission end, that had a bolt on U joint, and this was done because the frame had a crossmember that got in the way of removing the driveshaft, so you have to unbolt it at both ends, then remove the shaft, then pull out the slip yoke from the transmission. The bottom line: you need one slip yoke somewhere. Two slip yokes is kind of a no-no. The truck that we're talking about here is kind of hacked together, and could probably be improved upon.
Can't speak for this specific setup, but most non-Detroit RWD vehicles - and many Detroit products - use two-piece driveshafts, due to critical-speed/whip issues. If your wheelbase is short enough, or your rearend is tall enough, or you don't plan on exceeding 100mph, maybe you don't need to think about it. Otherwise...
Yes, center joint is there. what we don't see is the differential. Maybe it's one of them goofy grocerybag suspensions, Maybe it's 12 feet long?
Is this drive shaft set up causing an issue or are you just curious cause it looks so funky? Your set up is definitely not the way I would have done it, but that doesn't make it not functional. If it is working fine, you might be able to leave it. -Abone.
Not that I'm an expert in these matters, bit that looks like a modern set up with a OD auto trans and decent set-up, Farmers cut'n'try. Or maybe a little hokey [emoji12] The biggest issue for me is the finish of everything. Not the actual set up. But this might be on my account. But I know it's custom to leave the slip joint a little pre-slipped. So when the suspension travels it can go shorter a swell as longer. I've heart someone claiming 1/4 pre-slip out, at ride hight. And the move it true the circles, to make sure it doesn't bottoms out or slips out. But why is the part that can't move, lengthwise, is pre slipped? That makes no sence to me. But that can't come as a surprise to any one anymore. [emoji41][emoji111]️
It look exactly like the setup under my 71 GMC 3/4 ton with a turbo 400 except the front driveshaft is shortened up pretty short and you can see the weld and rust by the weld at the front where it was cut off and shortened. I'd say that it was a case of run what you have and not go out and spend a couple hundred bucks having a drive shaft built but if it works and doesn't vibrate what the hell, run it or run it until it acts up. A lot of these guys are scared ****less of a two piece drive shaft in a hot rod while their daily driver pickup has run one for years without an issue. If the truck is bagged it might be a blessing as you shouldn't have to worry about driveshaft clearance issues. The biggest problem I can see with that one is that you might have a vibration at speed if it isn't balanced. It it shakes or the carrier and center U joint give you issues on a continual basis change it to a one piece but otherwise there are probably better things to worry about on that truck.
I am doing a 47 chevy truck that has a 9' bed. It originally had a open 2 piece shaft in it. I am using a s10 2 piece shaft in it. The front shaft and mid bearing acually lined up with the original mid bearing mount. So I just have to get the rear shaft made a little longer(7")
^^Wow that was lucky.. I have the opposite on my Bantam, about a 2' bed. I made my drive shaft out of two slip yokes turned end to end. Here's the thread: http://www.jalopyjournal.com/forum/threads/a-simple-short-driveshaft.829164/
The Jalopy Journal
