Humming with Clutch Engaged

[Coastal220]

I know there will be no easy answer to this question, but please advise as to my course of action. 1970 220 with 4 speed.

When me clutch is engaged (pedal up) I notice a soft humming noise. Doesn't sound bad, but it's a noise, right? When I depress the pedal, the noise goes away.

Does this indicate my throw out bearing? What else could it be? How do you suggest I go about diagnosing this problem. Thanks all

[Frank Reiner]

Coastal:

I'm guessing that this occurs when the car is at rest and the trans is in neutral.
It is possible that the noise is from the T/O bearing when it is lightly loaded, but more likely the noise is from a combination of trans bearing and gear sounds. The noise abates when the clutch is released and the trans stops spinning.

[Coastal220]

Frank,

Thanks for your always fast replies. It does come when the car is at rest. Should have mentioned that. Is this anything to worry about?

[Frank Reiner]

Coastal:

Give this a try:
With the engine idling such that you can hear the noise, slowly depress the clutch; does the noise stop with a small amount of pedal movement (1-2 inches)?, or not until the pedal has traveled far enough to release the clutch?
If the noise stops with just a small amount of pedal travel, the T/O bearing is the likely source of the noise; if full travel is required then finger the trans.
If it's the trans, then a bit of whirring and humming are to be expected given the geriatric status of the vehicle.
If it's the T/O, monitor for increasing noise.