Knocking sound, pretty sure clutch related...

[klavender1]

It sounds like horrible rod knock but the noise goes away when you press the clutch pedal. And it's pretty bad if you shut the car off without having the clutch pushed in. Here's a crappy video I took. It's gotten worse since I filmed it. The clutch was replaced about 5yrs/50k miles ago. I replaced the pressure plate, clutch disc, throw out bearing, and pilot bearing. I don't abuse it at all and have driven manual transmissions my whole life. Any ideas what it might be?

http://youtu.be/wfc1_WgXbqg

[klavender1]

Any ideas?

[Marcos]

It doesn't seem to have a particular frequency. So I wouldn't tie it to anything connected to the drive-line (IMO). You may have bad mounts (motor/trans). The motor tends to oscillate more when it's shutting down and I bet you will see it move more than it should. It sounds like something is thumping against something else to me. Watch the exhaust when you turn her off.

I listened again, I really think it's not the trans or motor... my two cents

[Brandon12V]

I gotta agree it does sound like an exhaust knocking on the car. if it is your clutch and it goes away when you depress the pedal, it could be flywheel chatter. mine chatters but I have a jb racing 10lb flywheel. it's much more consistent though and has chattered its entire life. what clutch/flywheel did you put in? considering it starts fine, I doubt its the starter ring. if anything you may have snapped a flywheel bolt or pressure plate bolt and it's flopping around in there. did you use new hardware when you did the job?
Macros is right though. check for external clearance issues with the exhaust/bad mounts/etc before digging into the trans.

[klavender1]

Thanks for the replies. I'll check those mounts. I took it to a friend (who's a looooong time BMW mechanic) to refill the freon wednesday afternoon. He just said the trans is getting old and to run gear oil in it to get more life out of it. We didn't really dig into the problem. He was just going off of what he heard. I put some Toyota syntentic ATF in it a few months ago because that's what we had laying around the shop (it's got a slow leak). I think it's too thin for a trans with 285k on it and will go back to gear oil. I replaced the clutch with a Sachs OEM replacement. Don't remember about the hardware. He replaced it for me. I stood there and pretended to help. :D He's knows a whole lot more about it than I do. Haha.