Have a 2000 century with 86,000 miles. 3.1 Liter with 4t65E transmission. Have vibration thru car between 45 and 50. Rotated tires. Same problem. Looked at steering and motor mounts. All look good. Any suggestions what problem might be. Have not put it on scanner yet. Have to buy one since local repair shops in my area are very expensive.

 

Tie rod ends and control arm bushings could be another place to look if it's not the wheel bearing. Also make sure the lug nuts are tight, simple rookie move that we all do at times when we get flustered.