Hi everyone, my first post here. I've owned 3rd gens for a long time, but just bought my first 4th gen.

Anyways, it's a '95 Camaro V6 5spd. w/ 182k miles on it. When cruising down the highway, especially above 3rd gear, there's a bad raspy grinding sound that comes from somewhere. If I feather the throttle, the sound comes and goes, on/off/on/off. If I press the clutch the noise disappears, and if I coast in neutral it also disappears. The transmission shifts fine. No noise at idle in neutral.

At first I thought it was the rear end, but when the pinion bearing went on my Trans Am, it made more of whining sound that went away when I took my foot off the gas. I know a manual can make the rear end behave differently than an automatic though, since there's a load upon deceleration.

Any help is appreciated.

 

I see now I should have put this in the transmission section. Mods feel free to move it.

 

dont think its a trans issue, closer to clutch, sounds like the throwout bearing is failing or ccould be arrier bearing/driveshaft

 

sounds like the throwout bearing to me

 

Driveline noise can be a pain because noise travals through solids faster then air. Since the bell housing has a level of harmonic is common to think a sound comes from there.

Does the noise happen in 4th gear? and does the pitch change with the cars speed or the Engine RPM. Assumming it stays with car speed and it does it in 4th gear it could be the rear of the output bearing of the transmission. If it goes with engine RPMs and does not do it in 4th gear it could be your counter gear bearings. If it does it in 4th gear and it is with engine RPMs you are looking at a bad input bearing.

If the noise is staying steady with the speed of the car I would guess about 90% of the time its the rear. You can try swaying the car back and fourth while it is makeing the noise and see if there is any change. If the pitch changes its the rear.

 

The noise is really there in all gears, it's just more noticeable at highway speeds (above 3rd). And it does seem louder on deceleration then acceleration though. If I'm in 5th going 60mph there is a short sweet spot between acceleration and deceleration where the noise completely goes away, this is what I meant about feathering the throttle.

Everything I've read about throw out bearings says it should make a noise in neutral, but it makes no noise at all.

This is the only the second manual transmission car I have ever owned, so I'm not up to speed on what parts can go bad.

 

The whine/grind noise should change in pitch and how loud it is. Loud should be effected by load (car going up hill or you pushing on the gas) Pitch should be based on the speed the bearing is turning. Does the pitch change with the car speed or the engine speed. When you shift gear does the whine get start low and whine faster then when you shift a gain it goes back to low and builds up again or does it just start at 25 MPH and whine faster the faster you go?

I would not focue on the odd issue that in a certain situation you can make it go away. That is just a function of harmonic of a bearing. Most bad bearings have a place where where the sound waves cancel eachother out.

Do you have an Iphone or Ipod?

 

I recorded it with my iPad, but I cant figure out how to get it posted here.

After driving it again, the sound is pretty much during deceleration only. When I let off the gas and coast with it in gear (any gear) it sounds like I'm dragging something under the car. As soon as I press the clutch or put it in neutral, it's gone.

 

There is an App for vibration. It can tell was Hz the Vibration is at a given speed and just convert it to RPMs. Then you just figure out what is turning at that speed.

But before all that you should check your carrier bearing on your drive shaft. Jack the car up set the rear axle on stands and check the play.

 

Gorn, if you don't mind sharing an email address, I can send you the audio i recorded this morning. I tried posting it here but I think it's too big of a file. You can clearly hear the sound when I let off the gas.