Brake Pedal Vibration

[matt-jenkins]

The past few days Whenever I am on the Brake Pedal I get a pretty good vibration that I can feel in the Brake Pedal and hear. It almost sounds like something is vibrating against my Firewall. It only does this when the brake is depressed, even the smallest amount. As soon as you let off the brakes the vibration is non existent.
Any of you run into a similar issue?

 

[gatorman21218]

Could be a warped rotor. On the new cars if you panic stop you can feel the ABS pulsing but I have panic stopped on my truck and have never felt any pulsing.

 

[matt-jenkins]

But if the rotor were warped wouldn't it be more of a pulsing of the pedal and stop when the truck was stopped?
I've got the truck in the garage cooling down, im gonna go have a look to see if anything is vibrating against the firewall or something along those lines shortly. Think it could have to do with my torque converter since it unlocks when the brake pedal is depressed? and thats when i get the vibration. Its not strong enough I can feel it in my ass or the whole cab shakes, but I can hear it and feel it in the pedal.