My car has a vibration in the driveline.
At first I thought it was the u joints. I swapped driveshafts and it is still there.
The pinion has been leaking for the life of the car.

could it be a bad pinion gear or bearing causing it?

 

It could be an off-balance driveshaft, too! Try a different one, to see if it's still there.

 

He already swaped driveshafts. Make sure your rear whells are still in balance. Also you might want to look at your torque arm and mount to see if it is warped or broken

 

Oh, I'm an idiot. My apology!

 

It could be bearings happend to a buddy of man and he had to have them replaced. It sounds like thats what it is cause his was doing the same thing.

 

Thanks guys. I have had the tires rebalanced and it still does the same.
When I jack the car up and it is in gear the rear wheels still move some. is that normal?

I guess the feeling that describes it best it that is kinda shudders when I back up, then when I go down the road it is just a constant viibration and you can feel it in the tunnel, but not the steering wheel.