2006 rainier make a high pitched whining sound
Put your girlfriend/wife out at the next light and see if it continues.
Seriously, check idler pulley
I'm thinking more of a wheel bearing starting to go bad
Wheel bearing IS more likely
It's not the wheel bearing. It is the Idler pulley. The wheel bearing will make it feel like driving on a dirt road...it sounds completely different and doesn't get loader with speed...just turning.
Looking for a Used Rainier in your area?
CarGurus has 309 nationwide Rainier listings starting at $1,500.
Search Buick Rainier Questions
Buick Rainier Experts
Related Models For Sale