Well, chalk this up as a learning experience. Side exit exhaust dont do it!

Checked the drive shaft after work with a magnet base and dial indicator. In the middle of the driveshaft I only had 0.005 variance. I just think that it might be out of balance and that's it. Going to send it off to have it checked.

 

I assume this is a 1 piece drive shaft?
I’ve read how they amplify any sounds from the rear differential and how others have had vibration issues which they solved by rotating the mounting position. I’m not sure how that could help but could be worth a try.

 

Is it a harmonic type of vibration or a noise?

 

It is a harmonic.

 

Yes, one piece driveshaft. I have the DSS 9 inch conversion. Are you talking about disconnecting the CV joint from the output shaft on the transmission and rotating it a couple of holes and then bolting it back up?

 

Yes, I did read that this did help....was trying to find the article with no luck. I don't see how it would do anything myself.

 

I can see this helping if the bolts have come loose or loosened up a little or the flange was cocked to begin with, but who knows.

After looking at my situation I'm thinking that the bolts are the culprit. I have two that are not the same as the other four. I'm going to weigh them tonight with a gram scale and see what the difference is.

If they are a different weight I'm going to replace all 6 and then make sure that they all weigh the same before I install them.

 

Ok, gotta say I thought these cars had 2-piece drive shafts. Did you convert to a 1-piece?
Not sure about these cars but in the past when I did multiple shaft applications reclocking one shaft can make a big difference. Obviously, that doesn’t apply to a single shaft. I know you said the shaft had near zero runout but that’s probably not your issue anyway. Sounds like more of a balance issue. Any chance a weight popped off? If not, any chance there’s some kind of foreign material on the shaft? Road tar or something similar?

 

Yes, they are 2 piece stock. According to this guy, 1 piece DS are notorious for vibration.