anyone else having this problem? Dealership replaced tires and rims three times, replaced the transmission with a new one and car still vibrates. vibration is morenotable when sitting in the passenger seat.
has had this problem since new and now has 21,000miles on it.

any help would be appreciated

 

Check your muffler hangers and the 2 hangers in the middle that hold the catalytic converter and muffler. If the 2 in the middle break it will cause your vihicle to vibrate like you described. I know this as my impala did the same thing and I found out the 2 rubber hangers has dry rotted and broke.

 

Have the drive axles checked out.

 

Thanks for the input, will have dealership check it out