driveshaft clearance issues

[blackchariot88]

hello i just installed a 4"driveshaft in my 98 lsc and im having a horrible vibration over 70mph and it sounds like its rubbing on the gas tank as well any ideas on how to fix the issue with the clearance? Or do i have no other choice than to remove the shaft and start from scratch any suggestions will be greatly appretiated thank you.

 

[unity]

What did you find when you looked underneath?

 

[blackchariot88]

What did you find when you looked underneath?

I be looking today the guy I bought the shaft from said it's possible that the gas tank is positioned wrong.

 

[blackchariot88]

i repositioned the gas tank no luck i even removed both safety loops from the car as well im still getting noise and vibration if anyone has had this issue with a 4" driveshaft please tell me how you fixed it this has been driving me up the wall for the past week

 

[unity]

I assume the u-joints are new? Did you check the balance before you installed it?

 

[jbelcourt]

I assume the u-joints are new? Did you check the balance before you installed it?

^this. If you didn't replace u-joints, do so. If you did, the balance could be off on it.

 

[blackchariot88]

^this. If you didn't replace u-joints, do so. If you did, the balance could be off on it.

The shaft is completely new tube, u joints, and trunions are brand new it looked like it was balanceed as well maybe they did it wrong.