What is this noise my trucks making?!!?!?

Conditions, happens any and everytime I rev to a XXXX RPM. I dont know the exact RPM, but I have a m5od followed by the 3.5 or 3.51 rear end L/s. Finishing it up are 31 inch tires. In first gear, at about 18 MPH it comes in, and goes to about 21 where its at its loudest, and goest away around 24-25. Its a ratcheting whine, its hard to describe, its not a lifter or anything like that, because its continuous, not like a valve tap ect. Its louder and more pronounced on deceleration. If I am accelerating fairly quickly its less pronounced, but when I clutch to shift, you can hear it as the motor decelerates. I might try to make a recording of it on my laptop soon here, and list it somewhere. It does it in all gears at the same RPM and even at idle with clutch engaged, so i think the transmission can be ruled out, but I cant rule out the flywheel. Does this sound like a harmonic balancer? Its been in the truck since we got it, which was about 3 years ago, and rougly 18K miles ago. The truck has been driven to hell and back, and it hasnt as much as hiccupped, but the noise has persisted. Im not sure if its gotten worse, becuase I might just be exagerating it since Im thinking more and more about it, but it seems like it might cover more Rpms then it did when I heard it at first.

 

sounds like a throwout bearing going out.

 

I agree, my flareside was doing the same thing. Dropped the tranny one night and replaced the throw out bearing and has been quiet ever since.

 

thats a neg. Im on my 3rd throwout bearing, and its made the noise with the 1 that was on it when we got it. Then the clutch started slipping, and I put in a kit from advanced auto parts (after doing it the pedal got alot easier to push) as well as a new slave cylinder. After about 6 months, I was driving somewhere, downshifted ( a nice downshift to third at about 45 when it will do 70) and when i started letting off the clutch it kicked my foot off, then I pressed it in to go to 4th, and it went to the floor and staye there. The throwout bearing and or slave cylinder went out, killing the other. Found out the clutch kit wasnt to spec with the one that came out (the spines curved about 45-60 degrees, versus the replacement clutch in which the tips of the splines curled about 120 degrees. So after that we bought another slave cylinder and throwout bearing, and took the plastic shroud off the new one and threw it in there, and after a week it went off, so we got another, put it in just as it came outa the box, and threw it in there. No problems with the clutch since.
I have no idea what it could be, harmonic dampener/balancer? Has anyone had one of these go out before? Let me clarify the sound, its not ratcheting, its more of a whine, like i said it sounds terrible...

 

does the truck also go through alot of starters?

 

nope truck runs fine, doesnt go through anything like that, doesnt get bad gas mileage (actually got 18.08 on last 1, 65 constant round trip, and with 3.5 gears and a 4x4 i didnt think that was half bad... ne other suggestions?

 

well i thoughtd id bump this thread up a bit, and i seem to remember that the sound was least prnounced when I changed my belt. Still there, but covered the least amount of RPMs

 

get a stethoscope and start checking everything on the serpentine belt. might just be a bad bearing.