Date: 09 Jun 2006 19:05:17 GMT From: John B <rotten_NOSPAM_nospam.org> Subject: Re: bad drivetrain sounds (c900)
On 9 Jun 2006 19:28:23 GMT, Dave Hinz <DaveHinznospamcop.net> wrote: >> the most damning piece of evidence to me is that if the car is moving, clutch >> depressed, engine at idle, and in gear, and I then slowly release the clutch, >> as the engine comes up to speed the noise appears and speeds up accordingly. > > So it's on the engine side of the clutch then? Clutch disk itself or > something? Has it been slipping lately? This isn't making sense yet. > I'm thinking not clutch, because, for one thing, I don't think I'd be able to hear it if it were all the way at the front of the car. Also, the clutch was replaced a mere 30k miles ago. I rebuilt the MC a year or two back, and the pedal is totally firm (except when it's really cold out- but I think that's another story). I was thinking that if it is inside the tranny, could it be something to do with the shaft that has the gears on it and goes into the diff (I'm sure it has a technical name that I don't know)? > > Won't hurt but I think the above rules that out. Pilot bearing?!?!?! > Actually, let's think about that. The pilot bearing, on the end of the > clutch shaft, in the flywheel. Does that turn when you're hearing the > noise and as you describe? > Not sure I know enough to answer that question. > > One other thing I was thinkning - can you get the noise when the car is > just sitting still with the parking brake on? Would help diagnose it a > bunch, and eliminate the tranny/drivetrain side of things if so, and > reduces the options significantly. No, I haven't been able to do that. To hear it, the car must be (a) moving (b) in gear, and (c) clutch engaged. It's not distinctly audible much over 2000 rpm, because the frequency becomes too fast to hear individual 'clicks' or whatever. Can we derive anything from the frequency? It's roughly 4/5/6 per second around 1000-1500 RPM. This means that it's maybe once per every 4 revolutions of the engine, right? What is the ratio created by the drive chain? In other words, how many times does the transmission turn over for each revolution of the flywheel? John -- Posted via a free Usenet account from http://www.teranews.com
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