LWB driveshaft suggestions.

[shawn57nomad]

Hey guys and gals, Just wondering if anyone has a one piece drive shaft in their lwb 2wd truck. I would like to know if new is better or junkyard units rebuilt are okay too. If Junkyard shafts are okay what years of GM 2wd truck can I get one out of. I have sbc with a turbo 400 with a bolt on yoke if that helps any. All post would be greatly appreciated.

[Andy4639]

I was told it want work well. I just had my spare two peice done. For what it's worth.

[Bob 68327]

As far as I know gm never made a 1 piece shaft in a 2wd with a slip yoke built in it. You might measure some 4wd and see if they are long enough or change the tailshaft on your tranny and get a slip yoke . My 2cents , Bob

[69chevytruckin]

My friend has a 72 GMC with a one-piece. However when my dad called a good driveshaft shop in my area the master mechanic said it would not work to much lope.

[Andy4639]

You would have to redo the support where the center bearing rides now. With the angle it would have to be cut from what I have been told.

[shawn57nomad]

Cool guys thanks 2 piece it is...KNock knock BOB need drive shaft setup i,m thinking when u get a chance. Thanks again.
How does the setup measure with a bolt on yoke?

[brad_man_72]

at that lenth the diameter of tubing that would need to be used to not fail at a high speed creates clearance issues. save alot of time and trouble by sticking to a 2 piece.

[Bob 68327]

Mine has been over 90mph and it fits in through the hole where the carrier bearing used to be . I had it made a driveshaft shop and it wasn't cheap . I'm glad everyone here say's it won't work . It makes me feel better that I made it work with no troubles . The biggest problem I see with Shawn's is the bolt on yoke . With that he needs to go back to the 2 piece set up . Bob

[Andy4639]

Bob could you post some pictures? I was just told by the drive shaft shop it wouldn't work. I never went out and looked for anything. I just had my old 2 peice done since the other one was viberating so bad.

[Bob 68327]

I will try and get some up tomorrow . I'm not trying to be a smart a$$ It just seems every time this comes up everyone says it won't work . I have had mine for 8 years . No problems . I will get you some pics. Bob

[Lugnut64052]

It's a function of how big the tube is. Larger tubes dampen driveline vibration better. Our old trucks used a fairly small tube so they used a carrier bearing. Later trucks used a bigger tube so they were able to go to one-piece shafts.

The hole in the crossmember is big enough to to use a one-piece shaft. The cheapest way to do it is to get a junkyard shaft and have a driveline shop shorten and rebalance it. I just had that done to one and it ran about 75 bucks. Lots of guys have installed and run cut down one piecers with no problems.

If your transmission has a bolt-on yoke, your driveshaft will need a built-in slip. It'd be easier to have the slip at the tailshaft.

[PHAT TONY]

Machine shop here said they will make a shaft up to 78" long, that's 9 longer than needed.

[shawn57nomad]

Just measured the one pc in the garage and it is about 71" from joint to joint. the Diameter is about 3.5" is this going to be good enough for a shop to use for a one piece? Thanks guys.

[adpostel]

I'm running a 454 BBC with a TH400 Trans and have a one piece that was built at a local DS shop. It has the heavy duty greaseable U-joints and was fairly cheap to do. The measurement they will need is from the face of the output shaft on the trans to the flat portion of the yoke on the rear end, so that would be the first flat piece of steel you get to on the rear end yoke (just for clarification) Mine was 70.5 inches. The original bracket where the carrier bearing was will create issues fitting the one piece in. After hours of banging my head trying to get it to work, I finally took out the sawzall and just cut the bracket off. It went in like a glove after that. I don't know what the fuss is about, think about all the suburbans and trucks that had one piece shafts, why would the manufactuer put them in if they were unreliable. I'll take some pics of mine and post them up later today or tomorrow.

[adpostel]

Shawn, I don't think your one piece will work, go get the measurement that I just posted, that will give us a better idea. And I can tell you this, I had a th350 in mine before the 400 and i had to get one re-made, so i have a one piece for a lwb with a th350 trans in the garage.

[Bob 68327]

Pics of mine as promised . After I took these I felt a little embarassed that I still need to cut the trailing arm mounts off Here ya go . Bob

[Andy4639]

Thanks Bob. I should have done some more investagating on this before I had the old shaft done. I know now and will be looking for a shaft that will work for the future. Anybody have year models that will work?

[shawn57nomad]

HA! Cool....I will go with a one piece for sure. Bob and I talked today about it for 30 minutes or so and I would also like to see who else is running one. With or without a slip yoke. Thanks guys.

[Skirkpat]

My C30 has a 174.5 inch wheel base, can I get away with a 2 piece
it has 3 right now MY SHAFTS SO LONG I NEED BINOCULARS TO SEE THE END !!!!!

[brad_man_72]

its not really a vibration issue that im worried about. too long and too small of diameter tubing, the driveshaft can basically turn into a jumprope.
a good set of highway gears and a non od trans and your shaft could live forever. running an od trans and 4.11's driveshaft rpms can get high enough to kill a poorly engineered driveshaft.

[Longhorn Man]

there are many many variables
One that bob's points out, is ride height. His shoots straight to the rear, not much suspention travel. I don't think anyone needs to explain what would happen if his rear axle were another 4 to 6 inches lower, and then was unloaded like going over rail road tracks.
Rear suspention type is another important one. Looking at bob's again, with a pipe of that diameter, if he had a coil spring rear, which moves side to side, the shaft can and would probably tag the cross member.
Drive shaft shop. Many who will build one over 60 inches, SHOULDN'T
As far as the measurement directions go... call your driveshaft place, the directions above are NOT the industry standard.
Expect to spend quite a bit of money to get one done properly... esp if you need a slip shaft in the one piece shaft.

[justcuz]

Bob, since your rear end is spring under, the one piece driveshaft is fine. [I] would think a standard heighth truck should use a 2 piece shaft. I have one that has a slip yoke after the center support bearing so it doesn't push the rubber out with the rear axle movement. Came with my 65 truck and swapped it over to my 71 to avoid the support bearing troubles. Inland Empire Driveline Service makes one for longbed trucks with the slipyoke and a uerathane center support bearing instead of rubber. Last time I looked they were around 300 bucks complete.

[Bob 68327]

I agree that there are many variables and I would not say that this will work for every one . I had mine made by a driveshaft shop and it was around 400 bucks eight years ago and it weighs about as much as the rear end . I get frustrated when everyone says you can't do it . It just depends on your situation . Don't go out and put in a 1 piece just because I did . If your truck sits like mine does then I would say get one built and go for it !! If it's stock I would say leave it alone . Bob

[timcrow00]

so does anyone know what year of truck would make a good donor for a lwb or what diameter would work the best

[justcuz]

A 70's model 2wd with a simialr transmission would be the best guess. diameter wise I would say the smaller the better.