Randalla Posted November 16, 2009 Share Posted November 16, 2009 I've got a 1972 240Z with a five speed out of a 1981 280ZX. Now (couple of years after the installation of the 5-speed) I'm getting some strange noise I'm trying to diagnose before I drop the trans. when the car is idling in neutral without the clutch being depressed, I'm getting a noise that sounds a little bit like a rod knock, or marbles against metal. When I press in the clutch the noise goes away. When the car is moving in gear I hear the noise a bit but not as loudly. When the trans was installed I put in a new throwout bearing, pilot bushing, clutch, etc. Clearly it only make the noise when the clutch is locked up, which I assume must be something that is spinning under this condition. I'm guessing it may be the input shaft bearing on the trans. Any other ideas before I rip into it? The condition does not seem to affect drivablility at all but I'm guessing it's only a matter of time before something fails. Thoughts? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted November 16, 2009 Share Posted November 16, 2009 It's bearing noise. Could be input, I think it's usually countershaft. I've been told it can be related to the mainshaft nut loosening up. I have a friend who rebuilt her trans, and within a week it was doing it just as badly as before. She had it rebuilt again, same thing. I think that transmission has been in the car now for 8 or 9 years, still makes the noise, no other problems. If it bugs you you can fix the bearings, the question is how long will it be fixed for? Quote Link to comment Share on other sites More sharing options...
Sketch_hs Posted November 16, 2009 Share Posted November 16, 2009 If it goes away with the clutch in it may just be a bad throw out bearing .... Quote Link to comment Share on other sites More sharing options...
blackice280zxt Posted November 16, 2009 Share Posted November 16, 2009 I have spare transmissions for days...... all good Quote Link to comment Share on other sites More sharing options...
Flexicoker Posted November 17, 2009 Share Posted November 17, 2009 My transmission does the same thing. I took it partially apart, gears and bearings all seemed okay, so I just ignore it. Been driving it this way for over a year now and its been fine. Quote Link to comment Share on other sites More sharing options...
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