I have a 2005 f150 4x4 crewcab automatic. I have noticed that when i am driving and i have to hit the brakes hard (like a deer runs out in front of me) once i slow down to 20 mph or so i get a rather load tapping noise for a bit then it stops. I taps for about 3 or 5 seconds at about 2 to 3 taps a second. I believe it is coming from the transmission. Ive tried it a few times and it does it every time except when i put it into neutral then it doesn't make any noise. Anyone know if this is normal or if i have a problem or what