Working on a 2nd gen Olds Aurora and it has developed a significa.t howl between 30-50mph, peaking at 40-45mph. Definately coming from the front, possibly drivers side. Tires looks good with even wear and good balance, driver ft bearing is original with 140k miles and the passenger needed replaced this year. Noise does not change between straight/left/right turning nor with engine speed. Any thoughts?