Al Wheel drive

I own a 2005 Subaru Forester with about 30,000 miles. The tires were replaced about 15,000 miles ago and still have lots of tread. The tires are rotated about every 6,000 miles. My question is when turning a tight corner, the front end seems to make a vibrating noise. I have driven in a truch with 4-wheel drive and it also made a similar noise. Do you think it is a 4-wheel drive noise or is ther something going on that I should take care of. CV boots are OK.