Gearbox or Clutch noises

[David Mirylees]

OK, I'm getting old and the memory's failing and I should know this but...

I have just fitted a new (rebuilt) gearbox and all of the clutch paraphernalia. When driving the car I can hear a sound - rather like a straight cut gear noise - when the loud pedal is relaxed. The noise disappears when the clutch pedal is depressed.

Question is, when you depress the clutch pedal is it only the clutch plate that is free of the flywheel or also the first motion shaft?

Or, when the car is moving and in gear and the clutch is depressed, does the gearbox effectively still rotate being driven by the rear wheels?

Is the noise therefore gearbox or clutch?

Cheers, david.

[Exmog]

try tightening the clutch cable slightly. that is if your car uses a cable.

[Revin Kevin]

David,

The output shaft rotates with the driven wheels.

The first motion shaft (input shaft) and the layshaft and associated components are attached to the clutch plate.

When the relevant gear is selected the appropriate syncro hub locks the gear to the output shaft, unless it is a direct gear then the first motion and out put shaft are locked together.

When the clutch pedal is depressed the clutch plate is disconnected from the clutch cover and flywheel.

Although internal frictions of the box will cause the out put shaft to turn with the input shaft when not in gear if the is no force applied to the output shaft.

 

Hope you can understand my drivel and that this helps.

 

Cheers

Chris

[David Mirylees]

The output shaft rotates with the driven wheels. Understood

The first motion shaft (input shaft) and the layshaft and associated components are attached to the clutch plate. Understood

When the relevant gear is selected the appropriate syncro hub locks the gear to the output shaft, unless it is a direct gear then the first motion and out put shaft are locked together. Understood

When the clutch pedal is depressed the clutch plate is disconnected from the clutch cover and flywheel. Understood

Although internal frictions of the box will cause the out put shaft to turn with the input shaft when not in gear if the is no force applied to the output shaft. Understood

-------

But if the box is in gear and the car is in motion, will the internals of the box still rotate (as they presumably are still meshed and driven by the motion of the rear wheels) when the clutch is depressed?

 

[ECR]

Yes

[Johnty Lyons]

Wot he said plus the driven plate will be spinning between the pressure plate and the flywheel depressing the clutch just opens the sandwich and releases the meat [if you'll pardon my description] Thats why on down changes you blip the throttle to spin up the sandwich before it grips the meat preventing that jerk you get when your sitting beside the wife. [Drives me mad]

[David Mirylees]

Thanks chaps - it would therefore appear that the "straight cut" noise is actually clutch generated.

I take on-board the comment about the clutch cable and I'll pull it up a tad. I also see on previous posts that the CRB nowadays wants to be kept in contact with the housing fingers.

Any ideas on how to get a decent pre-load on a 1988 chassied car? (old type with no pedal box housing/cover)

cheers