New drive shaft new problem

[pnandy]

ok so i figured out my driveline vibration was b/c my drive shaft was about two inches to short and about to pop out so i had a new one made by a local shop dropped the old one out popped in the new one it drove like a different car until i got to third gear and the whole car started to shake like nothing before im thinking that the new one isn't balanced right i took it out put old one in thats to short  for now and the shaking of the whole car doesn't happen with the other driveshaft just the driveline vibration in high rpms  any thoughts ideas on what might be wrong?

[Midlife]

Take it back to the manufacturer and ask for it to be rebalanced. 

[daveSanborn]

Take it back to the manufacturer and ask for it to be rebalanced. 

Before you throw the towel in on the new driveshaft.... disconnect the rear u-joint from the pinion ..... spin the driveshaft/u-joint 180 degrees.... make sure the u-joint rotates freely (not binding) while it's installed onto the driveshaft......make sure both ends of the driveshafts u-joint are fully seated into the pinion yoke..... and then evenly tighten the u-joints back to tight.  Test drive.

If you still have the problem, then bring it back to have the balance checked.

[cmayna]

Sure sounds like a balance issue, but I'd be surprised that a company who just made this new driveshaft didn't automatically balance it.  WTF Mable?

[pnandy]

can't remember whats it called but after we took it off the part that connects to the u joint on the drive shaft that knob piece on the drive shaft fell off and it doenst have the bearing inside of it like the other side does so i at least have to take it back for that because its missing the guy built it real quick the paint on the shaft was still tacky when we picked it up i'll take it by tommorow to see whats up

[pnandy]

all fixed now had wrong size bearings on it and we needed to length the drive shaft a inch as it was measured wrong