The other week I took my Jeep in to have a sound I was hearing for the gear shift checked out. As always, they found something else that needed maintenance, my brakes allegedly. The guy told me my rotors and brakes needed to be changed so I declined because I'm not spending $400 for them to do what I can do. I change my brakes today and still had a considerable amount of break pads left on the rear. Why do I hear screeching however when I'm breaking slowly?