Possible input shaft bearing issue - Gearbox/Help Wanted

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Manindandism
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Joined: 09/08/20 8:59

Possible input shaft bearing issue - Gearbox/Help Wanted

Post by Manindandism »

Hi all,

My Rev 3 G Limited has started making a whirring noise with the clutch out. Gets louder with speed. Makes noise stationary in neutral also, but a fair bit quieter. Done oil change, no better. Clutch pedal in, car is silent.

What's the consensus on fixing this? Worth it? I'm pretty sore as I bought the car knowing it has a gearbox rebuild about 20k ago, so didn't expect it.

What's the cheapest fix? New box? Another rebuild?

If anyone is South Wales based let me know - or has a solid S54 box.

Thanks all.
Last edited by Manindandism on 09/08/20 10:52, edited 2 times in total.



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abovetherim
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Re: Possible input shaft bearing issue - Gearbox/Help Wanted

Post by abovetherim »

If when idling in neutral it makes this noise and goes away when you press the clutch it is more likely to be the clutch thrust bearing.

This is a known issue with aftermarket clutch kits, which was probably fitted when the rebuilt gearbox was fitted.

I have an excedy clutch a they have had issues with this but I have been lucky and my thrust bearing has held up so far. Some folks say use an OEM thrust bearing for peace of mind.
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Manindandism
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Re: Possible input shaft bearing issue - Gearbox/Help Wanted

Post by Manindandism »

abovetherim wrote:
09/08/20 10:20
If when idling in neutral it makes this noise and goes away when you press the clutch it is more likely to be the clutch thrust bearing.

This is a known issue with aftermarket clutch kits, which was probably fitted when the rebuilt gearbox was fitted.

I have an excedy clutch a they have had issues with this but I have been lucky and my thrust bearing has held up so far. Some folks say use an OEM thrust bearing for peace of mind.
Thanks, I'm hoping this is correct I paid for the car in knowledge it would need a clutch (last one done 15+ years ago).

However, most sources I've found have ruled out clutch bearings on the basis it's noisy when foot is off the pedal? Noise goes when pedal in down. Would a thrust bearing issue cause a rise and fall of the noise under speed also?

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Re: Possible input shaft bearing issue - Gearbox/Help Wanted

Post by SonicSW20 »

Manindandism wrote:
09/08/20 10:50
However, most sources I've found have ruled out clutch bearings on the basis it's noisy when foot is off the pedal? Noise goes when pedal in down. Would a thrust bearing issue cause a rise and fall of the noise under speed also?
Noise would change with RPM, not road speed.

Noise while clutch is not depressed is common, essentially the bearing is still just touching the fingers on the clutch plate so it is spinning but is not loaded (not 100% sure if it's supposed to, or if thats a result of incorrect install / incorrect pedal adjustment), noise goes away when pressing the pedal because you're loading the bearing.
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Manindandism
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Re: Possible input shaft bearing issue - Gearbox/Help Wanted

Post by Manindandism »

SonicSW20 wrote:
09/08/20 13:37
Manindandism wrote:
09/08/20 10:50
However, most sources I've found have ruled out clutch bearings on the basis it's noisy when foot is off the pedal? Noise goes when pedal in down. Would a thrust bearing issue cause a rise and fall of the noise under speed also?
Noise would change with RPM, not road speed.

Noise while clutch is not depressed is common, essentially the bearing is still just touching the fingers on the clutch plate so it is spinning but is not loaded (not 100% sure if it's supposed to, or if thats a result of incorrect install / incorrect pedal adjustment), noise goes away when pressing the pedal because you're loading the bearing.
Sounds hopeful, when coasting at speed (switching back to neutral at 50mph) the noise drops with the RPM drop. It's interesting the noise goes when the bearing is loaded fully - I figured it would be worse?

Thanks for the help

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