Maybe Brakes...maybe Rear-end?

[CHEVYFEVER]

Hello, I have a 02 Silverado 2500HD with 78k on it. When I brake hard I hear a clicking noise from my rear-end, not sure if it is in the brakes, or the dif. When I release the brake it is still there, and I can drive 5-10 miles and still hear it. I have taken to dealership, and of course they could not reproduce the sound... figures. I had them look at the brakes and they told me i needed rotors, and pads all the way around, and quoted me around $1200.00. When I got home I removed the tires, and the inside of the rear rotors had more wear than the outside, but still looked good, and had 80% of my pads left. Has anyone else experienced this clicking problem?

 

Thanks