I've wanted to post this for a while now. Above 90mph, I have a vibration coming from the drive train on my Z. It sounds like it could be the drive shaft, but it could just be noise traveling. Any ideas???

Thanks!

 

It sound like a unbalanced drive shaft (Technical Service Bulletin #674101).

 

My car was like this when new. After several tire balancing sessions at several different shops. And dealer replaced clutches and driveshafts. I replaced the tires (they were not wornout) Turns out my stock tires just could not be balanced. The new tires were compleatly smooth,quiet,and stable at 147 mph. The reason I did not go any faster was I did not know that with stock motor and gearing,160mph was only attainable in 5th. I was in 6th....so I started moddding.

 

I have vibrations around there as well with my stock 16's/tires on the car. When I put my 18's back on they went away. The 16's were bald if that makes a difference. Maybe its your tires.