Need Help Diagnosing A Vibration!!!!

[crow94]

I am a new owner of a 2001 base V8 with 90k miles and I have a vibration between 40-60 mph; the whole car pulsates/vibrates. Tires have been balanced twice and the car was put on a lift and with tires off the ground, the vibration was still there. 2 shops have told me that the transmission center driveline support looks "brand new".
There is no pulsation brake pedal, no drift left or right, new tires, shifts smooth....
What should I be getting checked out now?

 

[LS4me]

Bent wheel........ Loose shock mounting...... Failed shocks....

 

[crow94]

Thanks for the input LS4me...I hope more members will chim in with some ideas to check out.

 

[regiment1]

If it's happening with the wheels off the ground, then it's in the drivetrain, not in the suspension.

 

[joegr]

Road force balancing is recommended when you can't find any other cause. Also, if you do have a bent rim, this will find it.

 

[crow94]

Could a bent rim still cause the vibration off the ground??

If it's happening with the wheels off the ground, then it's in the drivetrain, not in the suspension.

 

[joegr]

Could a bent rim still cause the vibration off the ground??

Maybe, you are spinning a non-centered weight around. If it's not that, then it's most likely to be the driveshaft and/or its center bearing.

 

[04_Sport_LS]

??? To do a proper inspection of the center driveshaft support bearing... the back half of the exhaust has to be removed,,, along with the aluminum sheild that covers the transmission/driveshaft tunnel. If the shops you mention didn't do this,,, then they just peeked in there from one end or the other. Of course it would "look new". It never sees any weather. The driveshaft center support is a known issue with the LS,,, and the indicator is the speed at which you are feeling the vibration.

See this old thread:

http://www.lincolnvscadillac.com/forum/showthread.php?84411-Center-Driveshaft-Bearing-Part

Part number and price is in post #13