Wierd sound when cold
So this has been happening for some time now. Whenever it is below 10 degrees, my truck makes what sounds like a moderate to loud vibration near the passenger engine bay/tire. Here's the kicker, it only happens when the brake is pressed and the truck is stopped. So if the brake is pressed and the truck is still moving, no noise. Then when I stop, a loud vibration starts. It doesn't stop when I let off the brake. Only when I hit the gas it will stop. The noise doesn't happen when in park, it has to be in drive for all I know. It also doesn't seem to be harming the truck since it's been going on all winter. It just gets embarrassing when someone is in the truck with me and all of a sudden it sounds like something is going to break from it. Any ideas?
1999 XLT 4x4 3.0 Flareside
Off Road package, Towing package, 4.10's, 123k miles