Loud Clicking Noise...Front End or Tranny?

Yesterday I drove to work in 2WD, except in the parking lot where I had to use 4WD to get up into the parking space.

Last night I was taking a guy home from work and heard this loud clicking noise coming from the bottom, front part of the truck. It could be heard over the radio. He lives about 5 miles from work and by the time we got to his place the clicking was mostly gone.

It seemed to be connected to vehicle speed. I'd push the clutch in and give it gas and the noise would not change. It went away when we stopped and started again when we got going. It was the same whether we were going straight or turning. I started out in 4WD leaving the parking lot and switched back to 2WD when we hit the mains and it was still there. I can't remember (I was tired) but I think the noise was worse in 4WD. I don't remember being able to feel the clicking through the steering wheel or seat. As we got closer to his house the clicking noise decreased in volume.

Any ideas what this could be? The heater was just starting to work when we got to his place and when I started take myself home it was gone. I've got about 2500 miles on the truck.

I won't be able to take it in to Toyota for a few days at least. I'm working snow removal and we're supposed to get 5+" inches tomorrow so I'll need my truck to get back and forth. We're working fucked up hours...3PM to 3AM, 12 on 12 off.

 

Brake dust cover? Did you look underneath to see if you'd picked up a stick or other clinger? Take a look in the daylight, if you can.