24 Roadster

24 Roadster, Transmission Noise

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Is it normal to hear a roaring noise with the trans in neutral and foot off the clutch?  I know the 90 year old straight gears are noisy in first and second but I have a roar with the trans in neutral.  Over the winter, I replaced the front and rear transmission bearings with sealed bearings to stop leaks.  I replaced transmission grease with 1500 wt.  Do some of you hear the same noise?  When in third gear, sounds great.

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Not on mine.  Maybe clutch is mis-adjusted?  Any problem getting it into 1st?

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Does the noise go away when you depress the clutch?

 

Does it sounds like a dry bearing?  I am wondering if the noise is coming from the pilot bearing in the flywheel.

 

I replaced mine with a sealed bearing because there seems to be no way of lubricating it.

 

Ray. 

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The noise is not there when I press on the clutch.  Only when the trans is in neutral and foot off the clutch.  I have new sealed bearings in the transmission.  The noise was there before I replaced the trans bearings but it seems to be louder now.  That is why I wondered if this was normal.  I have the proper OD and ID bearings but I wonder if it is an internal clearance or a lub problem with the new bearings.

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From what you describe I doubt it is a problem with the gearbox bearings.  If the noise only occurred when you depressed the clutch I would have said it was the throwout bearing but as it goes away when you depress the clutch I would think it could be the flywheel pilot bearing.  To check this, remove the inspection cover and see if the driven clutch discs come to a halt when you depress the clutch pedal.  If the discs keep rotating, the pilot bearing in the flywheel could be seizing or catching.  This is not always the case however as the pins in the flywheel and the clutch can wear grooves in them that can cause the clutch plates to stick when they should rotate freely.  You might try listening to the bell housing (on the engine side) to see if the noise is more noticeable from there. 

 

Most gearbox noise comes from the top front sliding gear.  This gear takes all the input thrust and can develop a "wobble".  Try listening with the lever and lid removed.  I would stop the engine and smother the gear/shaft with bearing grease then start up again and see if the noise is still there.

   

Have you replaced the counter shaft bushes?  Perhaps new bearings on the main shaft have put the countershaft cluster under more load?  

 

I assume you have anti rattle springs on the clutch? 

 

Ray.

 

 

 

Edited by R.White (see edit history)

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I  have  the   same  problem  on  one  of  my  DBs.  Shifts   perfectly  but  a  lot  of  noise  until  you    depress  the clutch  pedal.,  Haven't  had  a  chance  to   work  on  it.

 

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Symptoms point directly to the front main case bearing.  It is where the input shaft enters the transmission.  It sits higher than the gear oil level, and would be the first to go bad on very low oil level.

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F&J The front and rear bearings have been replaced. 24 Roadster, Did you remove the inner seals on the sealed bearings? If not it is a good idea to do so as many of the sealed bearings have just enough grease in them to stop the balls from rusting. Remove the inner seal and they are then lubed by the trans oil the symptoms point to the input shaft and or the sliding gear as Ray suggested Hope you find the problem 

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6 hours ago, Ron Lawson said:

...Did you remove the inner seals on the sealed bearings? If not it is a good idea to do so as many of the sealed bearings have just enough grease in them to stop the balls from rusting. Remove the inner seal and they are then lubed by the trans oil... 

 

We learn something new every day.  That is new to me and makes perfect sense.  I now have to decide whether to strip down my newly refurbished 'box that is waiting to be fitted... 

 

Ron, our prayers have been answered;  rain.  We need it to rain a lot more and with luck it will.

 

Cheers, Ray.

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No, I did not remove the inter seals on the bearing.  I should have.  This makes sence because the pitch changed when I installed the new bearings.  Looks like another tear down when I get time.  Thanks for all the comments.

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I have just taken off the inner seal of the front bearing.  Ron, I see what you mean.  There is not much in the way of grease in there.

 

Ray.

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