In the last few months I have had a braking issue with my 08 GT. When applying the brakes continuously for 2-3 minutes or longer, coming down a long hill steep hill (mostly mountain elevations), I start to get a thumping sound coming from the front end and the steering wheel starts to shake. The harder you press the brake pedal the worse it gets. If you take your foot off the brake it goes away immediately. The brakes seem fine in every other situation other than very steep declines that require you to use the brakes for a longer period of time. I also noticed when it is wet (raining or snowing) after sitting at a traffic light/stop sign when I remove my foot from the brake pedal I hear a "popping sound" almost like the caliper is stuck for a split second (this only happens in wet weather). Of course I took it into my dealer and they said the rotors are not warped and the pads look brand new (44,000 miles), but it just happened again yesterday coming home from mountains. We are leaving for vacation June 5th and I am very concerned, because I have to drive through several mountainous areas on our trip. I am taking it back to the dealership this Tuesday. Anyone else noticed this problem or have any ideas what it could be? Could it be a caliper hanging up? Thanks!!