vibration at about 90 mph

[bsell]

Passed a car this morning in sport mode (3rd). Got up to about 90 mph/about 4,000 rpm and I noticed a slight rymithic vibration from what seemed to be the entire car. When I slowed down it went away. Never noticed it before.

My mechanic stated the giblo(sp) was showing some cracks. perphaps it is causing higher speed vibrations. Any comments? TIA

Easiest way to tell is get her on a lift, take the rear wheels off and run it up to the same speed and see if the problem remains. If so, then the drivetrain is causing the problem, not the tire/wheels or suspension.

If the problem is gone, then the wheels/tires are the problem.

Brian

[Russell]

Passed a car this morning in sport mode (3rd). Got up to about 90 mph/about 4,500 rpm and I noticed a slight rymithic vibration from what seemed to be the entire car. When I slowed down it went away. Never noticed it before.

My mechanic stated the giblo(sp) was showing some cracks. perphaps it is causing higher speed vibrations. Any comments? TIA

[Ross]

My money is on the driveshaft.

[swenpro]

hmm, I have the same 90 mph shake on my 540.. I just assumed it was a cousin to the 55 mph shake :D

[DanDombrowski]

I second this as I've been trying to track down a vibration in the rear of the car. Other thing you can do is rotate the tires to the front and see if the vibration moves to the steering wheel.

[whiskychaser]

Passed a car this morning in sport mode (3rd). Got up to about 90 mph/about 4,500 rpm and I noticed a slight rymithic vibration from what seemed to be the entire car. When I slowed down it went away. Never noticed it before.

My mechanic stated the giblo(sp) was showing some cracks. perphaps it is causing higher speed vibrations. Any comments? TIA
a. cats eyes? b. Can you drive 'through' it?