I found this out this weekend after hearing a grinding noise on my 04 1500 while I was braking.
Some brake pads come with a "brake warning sensor" that will emit a squealing noise when the pads are worn to a point where they should be changed. The front pads have them, but the rear pads do not have them.
I have always assumed the had them on all 4.
Anyhow, after 96,000 miles, I finally wore my rear pads out.
I had to remove the rotors and have them turned to get the groove fixed.
It is all good now, but I was pissed at the place that did my yearly state inspection for not noticing that the pads were almost shot.
Then again, I guess I should have checked them myself...
I hope others read this and don't make the same mistake.