Something is sliding around inside my driveshaft - any ideas?

[sadil340]

I brought it in for powdercoating and now something is sliding around inside the driveshaft. It is metal. Was there something welded inside the driveshaft to dampen vibration or something? Could the powdercoat process have separated it from the driveshaft? Of course the company that did the powdercoating has no clue.

[hotrod98]

May be weld slag from the when the ends were welded on. May have been jarred enough to loosen it up.??

[sadil340]

It's hard to tell from the sound but it seems like a bar not an irregular piece of weld or other junk. It slides smoothly from end to end and the clunk is pretty substantial so I would guess it's a piece of steel that had formerly been attached to the inside of the shaft.

[Katfish]

Was this a factory driveshaft?  How much did it cost to have it coated?

[sadil340]

Yes, factory shaft, $60

[Katfish]

Service manual mentions there is a Internal Vibration Absorber (IVA) inside the driveshaft.  I wouldn't think this would be metal, but maybe so.  Are you sure it's a metallic sound?  Maybe the IVA got seperated during the process.

Either way there's not much you can do about it.  I'd go ahead and run it and see what happens.
As a drastic measure you could drill a small hole in the end, and fill with that expanding foam to suspend whatever is in there.

Can you get an idea of how big the piece inside is?

[sadil340]

I was thinking it was some sort of IVA too. It's hard to tell the weight but I would say about a pound and it is definitely metal. The foam idea is intriguing. I can't run it like it is because the shaft was way out of balance already and they can't balance it with the part moving around inside. However, with the foam idea maybe it's possible. For now I'm going to have the balancer make me a new driveshaft and I'll figure the rest out later.

[6packCuda]

This is interesting. A friend of mine had the very same issue a while back. We never have figured out what the heck is was.

[Katfish]

Didn't realize it was that big.  It has to be the IVA.  I would think the foam would work. 

But I would try to figure out where they originally mounted the IVA.  If it's supposed to be in the middle, you'll need to add foam from both ends at same time so it doesn't get pushed to 1 end.

I just ordered a driveshaft from Mancini, it's $345 including shipping, u-joints & slip yoke.

I was thinking about getting it powder coated, but was concerned it might throw off the balance.

[farmertan]

hate to say this after coating but I would bring it to the local drive shaft builder and have him cut off one end get that piece out and reweld the end back on and balance shaft.

[hotrod98]

 

[NoMope Greg]

hate to say this after coating but I would bring it to the local drive shaft builder and have him cut off one end get that piece out and reweld the end back on and balance shaft.

  x10.  You don't want that rattling around in there and it would be just about impossible to re-position it correctly with the foam.  Plus, the foam itself could also throw off the balance.

[barracuda7199]

i bought a new driveshaft from mancini as well it vibrates like a madman!!! so be careful with mancini i didn't ship it back cause that would  !! but i do need to get it properly balanced though come to think of it.

[4Cruizn]

Maybe when the powder company baked your driveshaft, something inside was held in place by plactic or rubber . . and oh course after baking the shaft . . it melted and whatever broke lose.   

[Katfish]

i bought a new driveshaft from mancini as well it vibrates like a madman!!! so be careful with mancini i didn't ship it back cause that would  !! but i do need to get it properly balanced though come to think of it.

That scares me, how could you tell it was the driveshaft?