I'm sure they drove it. At least that's what I was understood that they did. And yes the noise is present any time the truck comes to a stop and when letting off. No way they couldn't reproduce it. Just wasn't worth their time to try to fix it I suppose.

 

I have swapped pads only a lot of times over my 22 years of owning vehicles, provided the rotors looked in good shape. The only time I have ever hears grinding on brakes is when you have metal to metal contact.

You should be able to see the face of all the rotors without taking a tire off. You should also be able to get your finger tip on the back face of each rotor. I would check them all out and see if any are scarred up. Sometimes debris can get between the pad and rotor and tear stuff up.

I would also check the ebrake.