The vibzzz are killin me!

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.............I've fixed a vibe by just rotating the shaft 1/2 turn and re installing it in the rear end yoke...............kim.................
 
TrailBeast said:
Yokes are not perfectly balanced.
Ever change the front one 180?
They should always be put back in the same orientation when ujoints are changed.
Seems like not many people know that.

I had a nasty vibration in the driveline, and one day just for the heck of it I pulled the driveline and swapped the front yoke 180 and the vibration was really close to gone.

The reason I swapped it was because the ujoints were new when I got the car, and I suspected the driveline may not have been assembled correctly.
Turned out I was right.
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x2
i had a vibe that drove my crazy.i have a new shaft built,the yokes were not correctly.i assummed the shaft was good because it was new.that one took me years to figure out
 
Well a little update, I pulled the shaft yesterday and took it to another driveline shop to check it out, I'll find out with that tomorrow. I did mark the shaft this time to be sure which way it goes back in and be able to turn it. I agree with supershafts that it shouldnt matter but heck I'm up for anything.
Moparlover-the vibe has been there for a while I just chose to ignore it cause I was doing the other things and figure "I'll get to it".
 
oldkimmer said:
.............I've fixed a vibe by just rotating the shaft 1/2 turn and re installing it in the rear end yoke...............kim.................
Click to expand...


Most likely the joint wasn't seated correctly and it went unnoticed and by changing it and putting it back the 2nd time you did wind up getting the clips seated correctly in the end yoke and not one side of the clip in the end yoke and other on the strap side which does have the ability to rock in the groove of the cap and make a .005 to .010 run out which has a dramatic effect.

Otherwise there is no way possible to change any part of the shafts shortcoming because of the end yoke.

If it has a issue in the end yoke it will have a issue no matter how it is phased to the end yoke.

The ONLY way it could have any orientation issue with a end yoke was if it was built and trued with that end yoke, and that EY has a defect and is out on one side.

The shafts at the time were made by detroit, they weren't making them with EY or balancing them with the EY from the diff, as far as i know they were using a inside clip fixture to hold the weld yokes into the tube for truing.
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I know people say its true, but if it was i could take a shaft swap the orientation on phase end on my yoke fixture and it would balance differently, it does not.
Same would be when i swap end for end and now the shaft is spinning opposite direction, nothing happens.
However dropping a shaft and it hits the floor just right can and does change the balance, setting a joint to one side of it's lock up and not setting the joint to center does change balance, which is very likely to happen in some EY's and these are tests i have done.
This is why very good EY are extremely tight on the joint and need light persuasion to instal the joint into, it's only a few thousandths and the shaft will have a problem

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Another update to the vibration quest. I had the DS checked at another place and they said it was .030" out, I had them fix it and reinstalled, no change. I rotated the shaft 180*, no change. I had the car 4 wheel aligned and the drivers rear was out by 3/16". shimmed it, no change. The car drives better than it ever has- im just fighting the vibes. I replaced the rear poly trans mount, no change. I replaced the passenger side poly mount with stock, no change. When I drive it down the road at 60-70 and kick it to neutral the vibes go away. When i rev the engine in neutral there are no vibes, When I put the car on jack stands and run it at those speeds its there. I removed the exhaust clamps from the tips, removed the muffler supports and set the exhaust on blocks, no change. Added weight to one of the pipes, no change. I dial indicated the wheels, axles, brakes and driveshaft on the car at the trans it has .019", at the center of the DS-.005" and at the pinion, .013". To me the shaft is still out. I have the car on stands today and with everything turning the vibes are there, when i pull the DS out and run it in 3rd gear and rpm no vibes:banghead:. Technically after 3 DS (original, new one built, new one supposedely fixed) by the measurements it looks like I need another driveshaft. Im down to DS, trans, or rearend. I also have a vibration app for the Iphone and it picks it up with the shaft in you can see the cyclic vibrations and when the shaft is out it goes away.
 
Cravin'sCuda said:
Another update to the vibration quest. I had the DS checked at another place and they said it was .030" out, I had them fix it and reinstalled, no change. I rotated the shaft 180*, no change. I had the car 4 wheel aligned and the drivers rear was out by 3/16". shimmed it, no change. The car drives better than it ever has- im just fighting the vibes. I replaced the rear poly trans mount, no change. I replaced the passenger side poly mount with stock, no change. When I drive it down the road at 60-70 and kick it to neutral the vibes go away. When i rev the engine in neutral there are no vibes, When I put the car on jack stands and run it at those speeds its there. I removed the exhaust clamps from the tips, removed the muffler supports and set the exhaust on blocks, no change. Added weight to one of the pipes, no change. I dial indicated the wheels, axles, brakes and driveshaft on the car at the trans it has .019", at the center of the DS-.005" and at the pinion, .013". To me the shaft is still out. I have the car on stands today and with everything turning the vibes are there, when i pull the DS out and run it in 3rd gear and rpm no vibes:banghead:. Technically after 3 DS (original, new one built, new one supposedely fixed) by the measurements it looks like I need another driveshaft. Im down to DS, trans, or rearend. I also have a vibration app for the Iphone and it picks it up with the shaft in you can see the cyclic vibrations and when the shaft is out it goes away.
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Was the shaft balanced or all they did was try and remove the run out ?
It sounds like all they did was try and remove run out and dick around with it.

Do you have all 3 of the shafts that you have tried, and if so can you take pics of all 3 shafts so i can see them, especially where the weights are on the shaft.

When you throw it to neutral and it stops is also pointing to angles
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The driveshaft yoke shoulder in the rear of the transmission should be 3/4 inch from the dust boot on the seal. This is called preferred static positioning. Hope this helps and don't require even another driveshaft length.
 
65CudaFish said:
The driveshaft yoke shoulder in the rear of the transmission should be 3/4 inch from the dust boot on the seal. This is called preferred static positioning. Hope this helps and don't require even another driveshaft length.
Click to expand...

There is also rearend angle shims and trans mount shims to correct improper yoke to yoke alignments.
 
Another update. I have checked the pinion angle and I figure its pretty good. I have 1 degree up on the trans and 1.5+ down on the diff. I have 2.5 shims in the car now and it seem to be the best but it still has the vibes. Ive been from 1 degree to 4 degree down on the diff and the more I go the vibes seem to get worse. :banghead:



 
Leave it where the vibes are best.

Also, did they BALANCE it or just remove run out ?

Are there new weights on the shaft Yes or No ?

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