I put new ujoints in my driveshaft, and now from 55 on up there's a slight vibration. i marked everything when i took the flanges off so it's back on how it was, and the new ujoints all move freely and easily. I'm gonna steal my buddies aluminum shaft this saturday just to make sure that's what it is causing the vibration. but why would it just start vibrating? could i have knocked it out of balance somehow since i was jerking it around a bit putting the new parts in?

 

i know you shouldn't have to re-balance your drive shaft after a u joint change but you may want to have it professionally balanced anyway, otherwise just buy a ford racing aluminum drive shaft...

 

well i took my buddies frpp one, and his was a stick so i put my trans flange on along with the new ujoint that i had already on that flange, and put them on his frpp shaft. bolted that in and it rides good again. so it's either the driveshaft is out of balance now or somethings wrong with that other ujoint.

 

Whack the U-joints with a hard rubber hammer, from a number of angles (rotate the d/s while whacking away). This will often force the joints to settle in to their natural positions after being remounted...

 

I did that before i put it in the first time.