Rumble in neutral!

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jmec
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Post Sun Jul 16, 2017 8:24 pm

Rumble from gearbox when in neutral, rumble goes when clutch depressed. Any thoughts/advice welcome. Thanks. 1990, 325i Cab.
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Stefan on probation
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Post Sun Jul 16, 2017 8:49 pm

Could be the clutch release bearing when it 5th does the rumble go away?
maxfield
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Post Sun Jul 16, 2017 9:02 pm

Layshaft bearing in the gearbox.

Very normal for a getrag gearbox, nothing to worry about.
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jmec
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Post Mon Jul 17, 2017 7:07 pm

Thanks for your replies. The rumble seems, always difficult to track down in a convertible, to go away when travelling in any gear including 5th. Also when cold at idle there's no rumble. So seems to suggest it is evident when the gearbox oil has warmed up which in turn seems to link in with Maxfield's diagnosis! Please let me know if this theory is tosh.
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Brianmoooore
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Post Mon Jul 17, 2017 7:31 pm

I agree with Maxfield and your theory, except that I'd describe layshaft noise as more of a rattle than a rumble.
there's a chance that your gearbox has been filled with ATF (to cure poor gear selection when cold) instead of 80 oil, which will make the rattle worse.
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jmec
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Post Mon Jul 17, 2017 8:52 pm

Thank you Brian. So I'm ok to just live with it? Next run out I'll review my rumble in view of your description of rattle. Could a different spec oil or additive help?
HartgeH27
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Post Mon Jul 17, 2017 9:17 pm

maxfield wrote:Layshaft bearing in the gearbox.

Very normal for a getrag gearbox, nothing to worry about.
Correct and spot on Jamie !