Help! Noise when downshifting.

[curtis325]

Help! Noise when really gettting on the gas.

I recently noticed that when I really get on the gas and the transmission downshifts, I hear a noise. Hard to describe. Could be a chirp or light rattle/knock. It's not very loud as I can only hear it with the windows down and stereo off. Almost sounds like it could be the serpentine belt slipping slightly. Noise doesn't change with a/c compressor on or off. Truck is an 05 V8 sport 2wd.

 

[curtis325]

Experimented a little on my lunch break. If I put the trans in 2 or 3 and really get on it, I hear the noise, even when the trans does not downshift. Also, it doesn't sound like the belt slipping. It's more of a knocking/ticking type of noise. Any thoughts?