Me and my buddy's dad tried to pinpoint the sound and it seems like its coming from the belt pulley on the passenger side of the motor and you can see slack in the belt as it slightly wobbles. When I turn my heat full blast the belt sequels from 1000-2000rpms then goes quite again we were thinking it might be a bad bearing in it. If it was a lifter or valve it would usually go away at higher rpms i believe which it doesn't so we kind of eliminated that I checked the exhaust and theres no holes and soapy water on the headers while cold show no bubbling so I'm doubtful of a exhaust leak. Let me know what you think.

 

Bearing in idler pulley.

 

i had a some ticking/rattling from the engine bay last winter, usually when everything was cold. i also had a second problem, where the belt would jump one notch off one of the pulleys.

unhook the belt from the tensioner and spin each pulley. listen/feel for dry, ringy, wobbly. or other problem.

my idler pulley bearing was dry and ringy sounding, so i replaced it. didn't help.
my tensioner bearing was also dry sounding - so i replaced tensioner pulley only. big mistake. it continued to rattle and continued to jump. i messed with it some more, and then the tensioner bolt stripped out, so i replaced the entire tensioner with a Gates from Advance. that fixed everything - the jumping/twitching, the ticking, and the belt jump.

 

I fixed the problem it was the pulley next to the alternator. I noticed while I was crawling under my truck that the metal bar that the trans sits on it all bent to hell I take it that's something I should be worried about lol? Probably from mudding with a 2wd truck stock lift. I'm really surprised about that though i thought i would've broke of my diamond plate running boards before anything but their hanging strong. I'm going mudding tomorrow so I hope my tranny doesn't end up in the mud.