Constant hum when I let off the gas while driving.

[waveoff]

Like the title says, when I let off the gas and coast I hear a loud hum from up front. The faster I go the louder it is. But I only hear it when I'm totally off the gas. If I touch the gas just a weeeee bit it goes away but then comes back when I let off. If I hit the brakes, it goes away but will somtimes come back. It hums when I'm in gear and it hums while coasting in neutral. Also, while starting from a stop I hear a clunk as I start rolling. Sometimes I hear the clunk after I shift to second and let off the clutch. If I'm driving and I blip the gas hard and let off immediately I hear the clunk. My car continues to run fine but with the sound it's making it sounds like something bad is going to happen soon. Does it sound brake related? Possibly tranny related? I put my summer wheels back on today with new Kumho 712's. When I first went out to testdrive my car it sounded, ran and handled fine. I did grind 2nd downshifting once, but no worse than before. When I went out a second time, that's when I noticed the odd sounds. Anyone ever experience what I'm talking about?

[blownLS]

I had a similar experience with a worn out engine mount. I ended up wearing and tearing all of the rubber around the shaft. On my car it was the front-driver side. I replaced it with a new engine mount, and beefed up all three with the polyurethane inserts. Engine does not move as much anymore, but increased engine vibration into the frame of the car by two-fold. Good luck.

[waveoff]

I have all three ES motormount inserts installed. I'll definitely check them out though when I look around under the car tomorrow.

[rjaffey]

Can you localize the sound; does it come from one side or is it more centered?

Does the pitch vary with the speed of the car?

[waveoff]

It seems like it's coming from the passenger side...possibly the tranny area. I can't be certain though. The pitch doesn't seem to vary, just the volume of the sound. The faster I'm going, the louder and more amplified the sound is. The pitch remains the same throughout.

[Holden]

Maybe your clutch hub is seperating from the clutch disk? This would explain the clunking when power transfer changes.

Does it feel like drive-train lash?

[waveoff]

I tried looking at my motor mount inserts today and noticed that the inner driver side insert was partially out. Both zipties that pass through the inserts were not secured. Also, the wheel on the A/C compressor was slowly grinding into the inner insert. I shoved the inserts back in but didn't ziptie them. I still get the stupid humming and clunking. Maybe my brake calipers are partially locking up? The hum goes away when I step on the brakes.

Greg--I have a bit of drivetrain lash but the clunk doesn't happen until like 2 seconds after letting off the gas. That seems like a long time after the lashing to hear the clunk. As for my clutch, it's the stock one with over 85K abusive miles on it. It still engages smoothly and I can still burnout with no problem. How would I check to see if the clutch hub is separating from the disk? I'm assuming this requires the tranny to be dropped.

[waveoff]

OK, this humming is still annoying the hell out of me. I stand corrected about hearing the clunk during drivetrain lash. It DOES happen at the exact moment the lash stops (which takes about 2 seconds). Also, I noticed that it goes away when I'm in a turn but comes back when the steering wheel is neutral. I'm getting damn close to taking my car to the dealership or something to see what the hell is going on.