High Speed Vibration 75mph +

[Galvatron]

Hello all,

I have a high speed vibration coming from the ass end in my TTA. It only does this at highway speeds starting at about 75mph +. The whole car shakes like a mother flower. It drives beautifully up until stated speed (indicating driveline, as in low speed, high rpm's = no vibration). I have been reading other forums (3rd gen f-body) and it seems to be affecting many cars. There are people over there throwing parts and money at their cars with 0 results. To me it sounds like a drive-shaft issue but I guess I just wanted to see if anyone here has had this same issue. Has anyone else here experienced a bad drive-shaft or a worn tail shaft bushing creating this monstrosity of a drivability issue on our cars? Thank you for your time.

 

[8289ta]

That does sound like a driveshaft issue. I had a similar problem years ago and it wound up being the yoke where the driveshaft bolts up to. The driveshaft may have, at some point been bolted on loose, leading to the caps spinning on the yoke and wearing it to the point that the caps would always spin on the yoke no matter how much I tightened the retainer straps.
I have also had similar issues with other cars where just rotating the driveshaft 180 degreees made the vibration go away. Have you removed the driveshaft lately? Did you mark it and put it back in the same orientation?
Either way, if you find a good driveshaft shop, they can make sure the driveshaft is balanced for a few bucks, and it would eliminate it as a cause, or luckily, solve the issue.

 

[Galvatron]

I have not touched the driveshaft but the first thing I was going to do was flip it 180*. I had the 4 tires professionally balanced today and it seemed to help a lot but there is still a driveline noise underneath but it does not vibrate as badly now. I think I have multiple contusions here. Flipping it 180* is what I intend to do and we'll go from there. Thank you for your input.

Any others with a driveline shimmy out there?

 

[TeeTopZ]

If the tire balance fixed some of the issue, it possible that the remaining vibration is due to bad u joints. Something to check when flipping the driveshaft 180°

 

[Galvatron]

Absolutely! Gentlemen, I thank you.

 

[pont1230]

Sounds like the u joints need to be replaced