I have started experiencing some terrible drive line vibrations, especially under load in 5th gear and at highway speeds. At first I started experiencing these vibrations when shifting from 3rd to 4th and 4th to 5th while disengaging the clutch slowly especially at somewhat lower rpm under a light load. It came in the form of a shudder that shook the car right underneath the center console.
I thought that perhaps the u-joints on the drive shaft on the transmission side were going bad and replaced the stock steel shaft with a 4th gen aluminum shaft with new u-joints. Unfortunately that did not cure the problem. The stock u-joints were fine and the new aluminum shaft only seamed to exacerbate the problem.
While I was underneath the car, replacing the drive shaft. I noticed that I had a small transmission fluid leak from the tail shaft housing seal. Not enough of a leak to cause a big mess, but a small seep. I pushed on the shaft up and down at the front u-joints and noticed a some deflection in the yoke with respect to the tail shaft housing. How much movement is normal? Could this be causing my vibrations? Is there a bushing there that could have gotten worn out? Any help would be greatly appreciated.

 

Yes, there is a tail shaft bushing. I replaced both my bushing and the DS yoke on mine back when I had vibration issues…it wasn't the cure for mine though.

 

Well, I am taking it in today to a drive line specialty shop in my area. I will see what they find out.

 

Any news? I am having a vibration issue. I replaced my shaft with a 4th gen aluminum one. The vibration disappeared on the first drive. After subsequent drives, the vibration is back in full force. It can only be felt from 45-50. After 50 you can feel it fade away, but you can also feel that it is sapping power out of the driveline. I really doubt it's anything in my front suspension, even though it's not in good shape and out of alignment...I would feel that in the wheel. This feels like it's from between and under the seats.

 

replace the bushing & seal if you see vertical slop in the yoke when you push up on it.