Yesterday I took off and upon my first brake, I could hear a loud clunking sound from the drivers side front tire area. I could fell a vibration and the more I drove, the sound and vibration decreased. The noise only occurred when I applied the brakes. Today I checked it and the sound was there but not as severe and it went away the longer I drove. Any ideas what this could be? I dont think its the brakes or rotors as I have replaced them about a year ago. The truck is a 2003 Crew Cab Silverado.