Driveline vibration help!
 

First and foremost, let me introduce myself. My name's Josh, and I am a new member of this forum. I apologize ahead of time if I am not posting this in the correct section.

With that out of the way, here is what I have been dealing with the past few days.

So recently I've been struggling with my FB driveshaft. Changed out the U-joints a couple of days ago but right after the driveshaft started making an awful vibration. No matter what I did, nothing worked. (The driveshaft or any other part of the car did not vibrate before the new joints, however it did clunk). I took it down to my mechanic buddy who told me that one of my yolk ears was slightly bent from using a clamp style ujoint puller and that that was what was causing the vibration. I am from Barrie, Ontario (Canada) so I then took the driveshaft down to Pat's Driveline down in mississauga to be repaired. They called me back after about an hour saying that it was done. To me it only looked like they added another weight to try and balance it. Anyway, I get home and install the driveshaft and it works flawlessly, no vibration whatsoever. After about 20 minutes of just driving my car normally, the awful vibration came right back and I have not been able to figure out why. I inspected the shaft for any damage or signs of wear, but to my supprise there was none. No play in the joints, the weight that they added was still in place. At this point I have no clue how to fix this or what to do. If anyone can offer any assistance, it would be much appreciated. I just don't understand how it would work without problem for 20 minutes and go right back to vibrating after it was supposed to be "fixed".

I'd like to add that I have not changed anything other than the driveshaft joints that could cause this vibration since there was none before. The only difference is that the old joints were non-greasable whereas the new ones are.

Thanks, Josh

Hi Josh, are you sure there was only one weight added to your driveshaft? Maybe they added 2 weights in different locations and one flew off. I'm just guessing. I've had a few driveshafts built over the years and some had one weight, some had 2 on different locations (usually a bent washer welded on).

yes, I am 100% sure that there was only 1 weight. I made sure to inspect it when they handed it to me.