So I noticed a while ago, that when i first start my car and come to a brief stop (before driving more then 50 ft at an accelerated distance) there is a terrible skreaching noise. However, after I drive for even 30 seconds over 30 miles per hour and then come to a stop, there is no noise. And there is no noise at every stop during a whole drive. What is wrong? I know its not my front brakes because I recently had them change, along with rotors and calipers in front. I have never had my back breaks changed, mainly because "firestone" has never told me i needed to. My car is 3 and 1/2 yrs old. Any comments welcome. Thanks