I determined that it was definitely coming from the caliper in the rear. I read that the sping mechanism sticks on these for some reason. I took some WD40 and lubricated the springs and other outer parts. One week later, it seems to be good. I will be having the brake parts cleaned and lubricated the next time I have it on a lift.
On a different note, put the Steeda cat back on last night and LOVE IT
Im glad I found this, I have the same problem but for a while now...over 3 months...lately since the weather has been getting warm and I have been putting my windows down the squeaky noise can be heard more and is very annoying. I am going to be looking at it within the week. I am 90% certain is has something to do with the rear driver side brake. Any suggestions before I start? I will be checking my springs and use some dw40 to lubricate the parts. I also noticed that the rear driver caliber has been under a significant amount of heat, since ive painted my calibers red and that one caliber is now black. I'm pretty sure this also happened after I had my 4.10 gears put in which does require the dis assembly of the rear calibers.
If you have a bunch of miles on the car the wheel bearing is probably what it is. If you are going to the trouble of replacing the one bearing just as well replace the other side while you have the dif cover off. Don't forget to replace the axle seals while your at it. Inspect the pads. If they are cracked (broke) this sound will be heard and go away while braking. Do not use lubricants on the pads. Once your pads get oil/grease soaked they are no good and you will not have fun stopping your horse.