I have a 94' Z28 with an automatic transmission. My problem is, there is a grinding sound (I think from the passenger side front). It seems to be the most noticalbe when the car is idling on a hill in gear, like waiting at a stop sign. It is also loud on take off and acceleration of anykind. Once speed is reached you really can't tell anymore. I just changed out the transmission mount. It was making the sound before I changed it out but i'm not sure if when the mount broke it messed something up. I checked a few things under the car to see if maybe a bolt had come loose on something but I can't seem to figure it out. Any help would be great.

 

Hello, that could be anything. You could try running your car on ramps so you can get under it while running to get a better listen. Have a bud put it in gear like this also, maybe you can at least find out what area the noise is coming from and go from there. Chock the wheels and put on your specks- safety first!

 

^^^ good idea do that and can u make a recording of it for us. could make it easier. could be a number of things. power stearing, belt tensioner, belt idler, alternator,

 

One thing I would suspect is the air conditioning clutch. It's not uncommon for a worn clutch to make a squeaking/grinding/groaning noise when it's disengaged. See if the noise goes away when you switch on the a/c (assuming the a/c works). If it does, you'll know that's what it is.

 

Well its more of a loud car shaking kinda noise. Like my first guess is maybe something is loose in the exhaust. I don't think it is front end to me it really sounds like it is coming from middle passenger side area and you can feel it in the center console.

 

-Update-

The sound is coming from the passenger side. At idle there isn't really any sound unless there is some weight in the car (someone sitting in the passenger seat or just putting your foot in the rear floorboard). Do you think that maybe one the exhaust hangers are broke?

 

That or part of the exhaust rubbing on a crossmember, rear axle, etc. Check your heat shields too, and the one that's attached to the top of the cat.

 

^^^ ya the heat shield on my truck rattles at low rpms. just above an idle. cant feel it but can sure hear it. only does it at a certain rpm. it being my dock truck i just live with it... lol

 

It was the exhaust rubbing on the cross member just like you said thanks.