Well after u joints, center support bearing I still get a vibration at varying speeds. Pulled the shaft and took it to the local driveline shop. He says mine is very strange because the harmonics are all over the place. He put a weight to one side, then imbalance shifts to the other. He puts a weight on the other, it then shifts to the other end.

He thinks it may have some sound deading inside, possible cardboard or foam that s lose and shifting. He can't answer for sure because it's the first Super Duty shaft he has worked on that he couldn't balance and has never cut into one. He said I can't charge you because I didn't fix it, so I have reason to believe he is pretty trustworthy.

He suggests I replace the shaft....... he didn't even quote me at first he suggested e bay or a junkyard, so he's not trying to sell me a new unit..but if that didn't work he could certainly build me a new one.

Can anybody concur before I go driveshaft shopping??

 

Sounds like he is inexperianced with truck shafts. I would find a shop that works on fleet trucks.The last shaft I saw was the one the owner ripped in two on his 550 and it had a little cardboard inside.

 

if you cant find one on ebay then the best bet is to just have one built. i had one built a few years back for a 51 f100 and it wasn't super expensive. he can even use the "ends" off of yours. the problem with most junkyards and drive shafts is when they use a fork lift to raise the vehicles to drain the fluids they more than likely they tend to bend the shafts.

 

I thought drive shafts were usually solid milled aluminum or in some cases milled steel?

I mean a hollow shaft would be lighter but even then why add the sound deadening material?

 

Driveshafts are hollow with sound deadening inside, usually cardboard.

 

x2, I used to build them quite often when I was still machining. If the cardboard is loose then yes, it will spin inside the tubing causing what the OP describes. Drivelines are (typically) made from mild steel or aluminum tubing, solid would be too heavy and isn't needed.

 

the answer is:

Sailboat fuel.

 

Thanks everybody for the responses.

Seems like the superduty shaft does have cardboard inside, and it seems as though mine has shifted or is lose and is moving around.

I don't like the e bay or junkyard idea...for reasons mentioned, PLUS the used shaft may have the same issue as mine. I will either go ahead and have them build me a new one, or see what I can do at the stealership....I looked it up at Tousley Ford, and without freight they can sell me a new one for less than I can have one built for...so we'll see.

 

Well, the correct thing to do would be to bring it back to the driveshaft guy and say "cut it open and fix it". You're going to spend money on it one way or the other, and having a decent driveshaft place make a brand-new/rebuilt one with yours as a guide is the right way to go.

And, it'll be balanced right - even a brand-new one from Ford can be screwed up from the get-go.

But that does look enticing to get one from Ford for less than having one made.

 

If money was tight, I would be tempted to drill a hole through the end of the yoke (stress free zone) and shoot some expanding foam into it and then get it balanced. If it works, done. If it doesn't, didn't cost much to try.

 

I thought about having him cut and lets see just whats inside. He said he could reuse my yokes and slip joint if I want and he could make up a new shaft for me and save me some cash, but I can get a Ford part for within $100 of his and everything will be new. He also said if I get a new Ford piece he could check the balance on that too.....Plus every time I try to get cheap, something screws up and it ends up costing more than if I just went the "more expensive" way to start.

 

I actually thought of doing that. Figured if I have to replace it anyway one way or the other, it can't hurt to try this.

Although I did speak the the driveline shop owner today and he is shying away from this. He is thinking that since the harmonics are moving up abnd down the shaft, it could be that and possibly a combination of other things working together to cause the issues I am having....I guess basically the only way he can guarantee it is right is to rebuild the entire shaft, or replace it with a new factory unit. I just don't think he would turn down the business and he seems like he knows whathe is talking about since he doesn't really want to try and experiment. He only wants to do what he knows to be proven.

Plus, I don't think he wants me coming back in every week with the same problem and he ends up working for free.

 

Could be the slip shaft just flat out wore out. Mine was shot at 195K miles. Actually my slip yoke had a bunch of play in it, and I twisted the shaft, only way we could tell was it was dented in on one side. You also could have twisted yours somehow and you just can't visibly see it. Most driveshafts are same thickness as exhaust pipe, sometimes it doesn't take much to put a little twist in it.

I wanted a unbreakable driveshaft so I called Jess at High Angle Driveline and had him make a whole new driveshaft with a new 1350 series CV and a 1410 joint at the pinion yoke. Super easy to deal with as he builds shafts for sled pullers, trophy trucks, and rockcrawlers. It's cheap insurance as I'm pretty hard on my truck. Nothing wrong with a factory Ford shaft, I just wanted to upgrade.

Regardless it sounds like you just need to order a whole new driveshaft and fix it right the first time.

 

Sailboat fuel..... aka....whole lotta nuttin, sound suppression ? I can hardly hear the radio...a straight piped 7.3 is all the music I need