squealing noise

Their seems to be a continous squealing noise coming from my front end. It starts at about 10mph and on up. I have come to the conclusion that it is either the brakes or transfer case. The noise seems to not change when i hit the brakes just keeps going until i get below 10mph. It sounds like when your pads go out and the wear indicators are doing their job. But i just replaced the pads last weekend so i know it is not the pads i kind of think it is a frozen caliper maybe? But i have no idea how to check and see if that id the problem any ideas. My truck is an 01 with the 5.0 and it is AWD with four wheel disc brakes. thanks in advance for any help. I know it is a mountaineer but i believe alot more people subscribe to this link than the mercury one.

mountaineer same thing as an explorer
navigator luxury version of the expedition

mountaineer same thing as an explorer
navigator luxury version of the expedition

Yeah i know and the Aviator is the same as the explorer and also the ranger is pretty much the same as the explorer. But i need to fix mine so this does not really help thanks anyway.

if you think it is a caliper problem check them to see if they are actually frozen by cracking the bleeder valve and having someone depress and hold the brake if fluid comes out your ok close the valve then let off the brake try the same for the other(s) If that dont work then good luck..maybe tighten your belts i dunno!