I heard a scrunching sound coming from the front wheel wells of my 2004 Chrysler Pacifica. I took off the brake pads to look to see how much life remained and to determine if this was the source of the noise. To my surprise, there are no wear sensors on these. There was some remaining life on the pad material. These are the original factory pads and the car now has 57000 miles on it. Do they make the pads near the backing plate out of a different material so that it emits this noise these days?