i have a 2008 cobalt and when i go over bumps or drive on gravel roads it rattles like crazy. I have read online that it may be the steering column. I also found a service report 04-03-08-006D basically detailing this problem and stating that it may in fact be the steering column needing replaced. it has 54000 miles on it and i was curious since there is a service bulletin would GM still be required to replace it no charge. thanks