Idk if you solved that noise in reverse but I have the same truck and it does that damn whining noise in reverse to. I've taken it to a bunch of mechanics and they have never figured out what it is. It doesn't do it as much as it used to, but it does it randomly here and there. I just had my pads and rotors replaced to fix a noise I had coming from them. Buddy owns a shop so he hooked it up. But he also said that one of my Caliper pins was seized up or something like that causing a squeaking noise. I don't know if this helps. I will try to figure out exactly what it was he said to me and I will let you know.