Knocking / rattling / clunking clutch or gearbox?

[Steviebaby007]

Hi all,

Looking for a bit of advice with a rattle that’s been driving me mad on my Minor. The noise comes in when I’m moving, sometimes in neutral too, but it tends to quieten down completely when I press the clutch. It’s a constant knock/rattle that speeds up with road speed when in gear.

So far I’ve:

Changed the UJs on the propshaft.

Changed the clutch linkage assembly

Added the anti rattle kit for the gear selector

fork and thrust bearing look fine

The clutch itself is only a year old.

Distributor and leads all seem fine.


At first I thought it was engine related, but it really doesn’t sound like it. I’m now leaning towards gearbox layshaft bearings or something similar, but would like to hear what others think before I start pulling things apart. I uploaded a clip here of the noise: https://youtu.be/tfXgdiIMlfE?si=jlCjA0-dAkd-ZwgB

Anyone had similar symptoms?

Cheers,
Steve

[King Kenny]

It sounds nasty but I can't think what it might be. It does sound dry, Is the cooling fan hitting something?
My dad once asked me to check his Robin Reliant as he thought he needed a new gearbox. I took it for a drive and found that the air filter cover was loose.

[geoberni]

Sounds like something with far fewer revolutions than anything to do with the engine.

Not whiney enough for Diff IMHO, but "when I’m moving, sometimes in neutral too" is confusing as it sounds related to road speed....

It's hard to tell what it might be, without hearing it 'live' including from outside the car....

[Nickol]

Had a similar annoying noise, not dissimular to yours.

It was the engine steady bar in which the rubbers were perished and the bar kept knocking against the bare metal.

[svenedin]

I don't know what that noise is. A long time ago I had something similar but worse. It was a damaged tooth on one of the gears in the gearbox. It rapidly got worse and I needed a rebuilt gearbox. What is the relationship between the noise and the road speed? Does the tapping get faster the faster the car is travelling regardless of the gear selected? Can you get somebody to stand outside whilst you drive past? Maybe it will help narrow down where the noise is coming from.

Stephen

[oliver90owner]

When you say it goes away when you press the clutch, do you mean operating the clutch while stationary?

Can never be sure but, if so, I would expect gearbox trouble as the only thing changing is the gear shaft(s) stopping.

[Mervin]

Pedant alert. "Robin Reliant". Reliant Robin.