I may have asked about this before (may have been on another forum) but I'd thought I'd give a shot anyways. I've got this weird rattling sound that comes on at around 3000 rpms in every gear. If I push the clutch in, it goes away. If I let off the gas, it goes away. If I get to about 5500 to 6000 rpms, it goes away. I first noticed the sound a long time ago, but it only seemed to happen in 4th or 5th gear (interstate travel). Now I notice it in just about every gear. It's quiet enough to where if I listen to music or have the windows down, I don't even really notice it. But if I''ve got the radio off and windows up, it's definitely noticeable. Any suggestions? My first thought (and what would be way cooler) was that it was just some loose piece somewhere in the dash, but it seems to be pretty consistent with the rpms. As soon as I heard the noise I took it in to Subaru (in Augusta) and they couldn't find anything wrong with my car. S basically I'm thinking, somehting internal with the tranny, an exhaust leak, or just some loose piece in the dash. Anyone have any ideas or have had a similar problem? By the way to me it sounds like it's coming from the left of the steering whel, but most passengers say it sounds like it's coming from behind me. edit This may be in the wrong section. Sorry guys.
^ What he said. When you engine is engaged with the drivetrain it has a tendency to put more vibrations into the exhaust, because the engine cannot dampen it out it all gets transfered into the exhaust. When the exhaust gas is flowing at high velocity is has very directional flow, which prevents vibrations.