Today when I was parking the car in the garage I noticed that there's a sound when the clutch is engaged on neutral. When I push the pedal and the clutch is lifted the noise goes away and when I release the pedal the noise starts again. Its not exactly rattling, its just ... noise. It doesn't sounds bad but its there. What is it? The clutch is brand new "Exedy" on less than 1k km so I doubt its that.I guess the sound is there when I am on actual gear, not just on neutral but I noticed it just now.

Sounds like main drive gear bearing.
They can go a long time growling and rumbling before they are a problem.

Is it possible this sound to come because of low oil level in the gearbox?

Yea, that sounds like the bearing on the main input shaft of the transmission. Low oil level in the gearbox definitely could have damaged that bearing and lots of other things inside the transmission. I would get it filled up to the proper level ASAP. The damage is done, but at least it won't get worse.

So what now? I just fill up the tranny with oil and drive until the s*** hits the fans (whats going to happen then?) ? When the s*** is already in the fan, I have just to replace the bearing or the whole transmission?

They get noisy with normal use, generally after a lot of miles, correct oil level or not.
The countershaft bearings will get noisy next (if they are not already).
Their noise will be most noticeable in 1st gear and get less noisy shifting up through 3rd, then go away completely in 4th.
Time for an overhaul when you can't handle the noise anymore.

Yesterday I was listening for this noise when the car was running but tbh I couldn't hear it. I don't know if it was because the car is too loud to hear it when its running or just because the noise is there only on neutral gear. I will fill up the gearbox with oil today and will see if it will goes away.

Any shavings in the oil or on the drain plug magnet?

I don't know lol. I was too lazy to get under the car so I decided to fill the oil from the above by removing the shifter. I am still not done though. I think it would have been easy if I actually jacked up the car and lied underneath it but its too late now :\

The noise will just keep getting worse. You'll know when it's time for a rebuild. The noise will be unmistakable.

Well, the gearbox is running really nice. I never had any problems with it. It shifts like Winchester rifle. I never had any grinding or anything.

30K wrote:I don't know lol. I was too lazy to get under the car so I decided to fill the oil from the above by removing the shifter. I am still not done though. I think it would have been easy if I actually jacked up the car and lied underneath it but its too late now :\

How did you get the oil to the correct level that way?
Did you have the fill plug out?

themadscientist wrote:Any shavings in the oil or on the drain plug magnet?

If the trans has been in operation for any considerable period of time there will always be some metallic debris on the magnet. This is normal.
If you find teeth or pieces of shim etc., that's an indication of major failure.

ezb57e wrote: How did you get the oil to the correct level that way?
Did you have the fill plug out?

Anything above the middle is good, imo. As I said the gearbox is doing fine - no screeching or anything, so I assume it had at least 1 litter in it. I just poured another litter so it should be above the middle point anyway.

just FYI, if you get it too full, it will leak from the rear shaft seal. Guess how I know about that? LOL