i tryed everything you guys offered and i even replaced the a/c compressor. whn i replaced the compressor the noise quieted down alot but the next day the noise came right back. my only clue is that at 40mph thew noise cuts out for about an half of a second and then kicks right back in. i dont no what that could be. i checked almost every pulley i have to double check the p/s pump and i found that the alternator pulley has a wobble to it when i spin it the pulley wobbles like it is bent. any other ideas or testing would be greatly appreciated. also i bought my belt at autozone which is the belt specified for my truck is it any difference then going straight to ford and buying an oem belt. thanks

 

The non OEM belt won't be a problem, especially if new, and did you ever start the engine with the belt removed ?? It would prove out the belt as well as a possiblity.. If it 'were' a case of the distributor shaft/housing running dry, it makes (or can) a horrible 'sqeaking', sometimes 'chirping', and will still be present even though the other drives/pulleys/belt have been eliminated from the equation with a belt removal.. Make sure the center nut (its just a pinch fit pulley) on the alternator is tight if you haven't already, and if its just a case of the pulley being a bit unstraight, it shouldn't create a squeak. Is this noise more temp sensitive, and present only during hot/cold driving conditions? Worse at idle, cruise ect.? I NEVER said this, but,...One of the tricks to use to check for a glazed squeaking or 'creaking' belt (especially if cold and damp, with an older belt) is to spray a 'small' amount of WD-40 ect. to the running surfaces of the belt (idle).. If the noise is 'instantly' eliminated, than it's a belt/pulley issue.. Idlers, alternators, A/C bearings, pumps will not quite from a 'topical' lite spray.. The WD will dissipate 'very' quickly, and must be used 'lightly' so not to fling off.. Not recommended for a new belt, but works well to diagnose an older glazed belt, from idler concerns ect. prior to replacement.....

 

It is a good idea to pull the belt off, I had the same thing on my 95 f-350/351. It was my alternator. You can also use a vacume hose about two feet in lenth. Use it like a stethiscope, (stay clear of your fan ovcors[sm=nxsmile.gif]e )