Like said in title, my truck now has a squeaking sound like a little bird chirping at low speeds, and it does it louder when I throttle up some. Not as bad when I let off and coast or back up. Seems to be engine rpm related as it speeds up with rpm's if I goose the throttle a little and the rpm's build before speed increases. That is what has me a little confused. I have had u-joints go bad in the past and I have heard the "bird chirp" sound (probably due to the no-grease condition) but it was SPEED related with driveshaft speed and not engine rpm. Anyone with some clues on what to check? It doesn't have any vibrations and the u-joints feel and look okay.

 

Sounds like a U-joint to me

 

I agree U-joint , seem's like the rear ones wear out first in most cases . Drive it a few miles , than go under and feel for heat in the u-joint , the bad one should be warm .