The first thought is starter and/or flywheel. It sounds a lot like metal interference. 1996 - GSX - Manual trans. New stock style clutch and pressure plate , resurfaced flywheel, less than 10,000 miles ago. Driven it quite a bit since new clutch. Sound started a few weeks ago, and then got worse. First thought was starter, went in to check that and found it loose (that's bad), tightened both bolts. Problem is still there. Pulled starter out and check with charger then battery for solenoid action and motor spin. Was okay, but thought it could do better. No noise from starter at all. Let auto parts store run a test and it passed, but we all agreed that solenoid was sticking a bit.... purchased a re-manufactured starter. With tremendous confidence installed the new starter. Still have loud noise when cranking, but runs great, car starts quickly. Thinking low battery might somehow play a role I jump started from another car during starting to add extra amps, still bad noise during start. I am now out of ideas and nothing in the service manuals deal with noise, all the troubleshooting is for starters that do not start. There does not appear to be any way to shim or alter the way the starter sits. You simply tighten the two bolts and nothing more to it. It has the typical sound of starter teeth hitting flywheel. But without being able to adjust the starter / flywheel distance I do not know what to do. Any ideas greatly appreciated. We recorded the sound with a phone-camera but I don't think the sound comes across on video. Anyone ever had this problem ? Some Notes: Just got under car to inspect. Studied the trans to block bolts, motor mounts, opened flywheel inspection plate as much as possible (transfer case gets in way), took good look at old starter to look for metal fragments and teeth wear. Nothing yet jumps out as obvious, but the flywheel teeth I can see do show the kind of early shiny wear associated with grinding. I am going to remove all the intake parts and battery box again and look carefully at how the new starter seats into the block. Hard to do with all the hoses. Car is basically all stock with AC, cruise control, etc.. One more thing, I tried starting with clutch pressed in, and clutch out, did not change the sound at all. Although I keep thinking I can feel it through the floorboard, of course the starter is right behind the wall there.