Hey everyone, i have a 2004 chevy 1500 and when im doing 75-80 on the highway or i get on the gas goin up a hill in 4 wheal peal, this is this wierd noise coming out of my heater vents on the dash, at first i thought it might be something to do with the four wheal drive because thats when you hear it the loudest but i just noticed that when im on the highway it quietly makes the same sound. what it kind of sounds like is something loose in the heat vent that is getting blown around but when i turn on the defroster there is no noise. so this one here has me stumped...... any suggestions??

 

er not the damn heater vents the defroster vents.

 

i've not seen that,no...you have to be in motion?

 

My dash is sort of like that when I took the side pillars out the front of the dash in the left corner made a vibrating noise because it was bouncing up and down slightly from my dumped exhaust. Try holding down your dash in the bottom left/right corner near the end of the pillar to see if thats whats making the noise unless there really is something cruzing in there. <.<

 

I know my Sierra has a problem where the gears behind the dash that control the air flow get stuck on for some reason so they keep cycling on every few seconds. At first it was only with the airflow pointed at you but now it's also the defroster.... Annoying as all get out!

 

well so this is another piece of the puzzle, i found that if i hold the 4wd shifter on the floor tight either agains the 4wd or N the noise goes away >.< so that is kinda wierd, but makes me think that it just a vibration in the linkage and nothing crutial hopefully.

 

Mine does that too!

As for the sound, I dont know what it could be.. but mine had been making a "slapping" noise when acclerating just before downshifting, and I think its just piston slap. [sm=smiley21.gif]