Rattle from the gearbox......

[baconbuttyman]

just had the RAC man out to the car, there is a slight rattle coming from the gear box, he seems to think its the lay gear, what is this and is it serious :shrug:
thanx guys

[Phil]

Is it at idle and in neutral, does putting your foot fully on the clutch stop it? If so does slight pressure on the clutch pedal change the pitch?

[baconbuttyman]

inneutral, the noise is there, when the clutch is depressed it disapears

[Phil]

Ok, what about if you take up the first half inch of free play on the clutch pedal?

[baconbuttyman]

so younare saying it could be free play in the pedal :shrug:

is it worth changing the gear oil, if so which is best

[COLVERT]

Could easily be crankshaft end float. ie. Slight wear in the crank thrust bearings. Will go away with pressure on the clutch pedal cos this pushes the crankshaft in the direction of the crankshaft pulley.
Can be slightly annoying but rarely causes any problem other than a light knock.


Colvert.

:mad:

[COLVERT]

inneutral, the noise is there, when the clutch is depressed it disapears
If the noise is coming from the gearbox then the reason it goes away when you push the clutch pedal down is that the innards of the gearbox stop revolving. Also my post above is relevant.



Colvert. :party::cool2:

[Phil]

so younare saying it could be free play in the pedal :shrug:

is it worth changing the gear oil, if so which is best

Hello Mick, the reason for taking the freeplay out of the pedal is it loads the release bearing but doesn't stop the gearbox from spinning.:)

[kraanc]

Hi. I have the same problem. i can hear light rattle at gearbox, and have pedal freeplay also. How do you take out freeplay?

[mh007]

The whole idea of taking up the free-play on the clutch pedal is just to try and eliminate certain areas.
The Layshaft/Gear will rattle when the car is idling in Neutral & the noise will disappear when the clutch is depressed (if there is wear apparent)
If the noise is still there when the clutch is depressed, it's not Layshaft/Gear related & may possibly be clutch release bearing.
Incidently, Dual Mass Flywheels (DMF) can also rattle when they are worn.
I've had gearboxes go on for ages with Layshaft/Gear rattles without problem, just more of an annoyance.
It would be an idea to check the gearbox oil level.
Trying to permanently take out the free-play in the clutch pedal will not cure the problem & is not recommended.

[Mr_Shed]

I think it is a trait of lot modern cars now as the oil is synthetic and quite thin in comparision to the old EP90 days, had same noise on my bmw 320 and old 214.

My 190 also does this when the car is at standtill with the engine running, the gearbox main/lay shafts have 4 to 5 gearsets on them with no load so tend to hunt or rattle, this is not uncommon but in conjunction with modern oil as stated above doesnt deaden the sound so much. I changed the oil recently, as maintainance item and it came out clean with no debris etc so not expecting any problems.

Reason for pressing the clutch as mentioned in earlier post will disconnect the gearbox from the engine rotation therefore should be no noise. If noise continues or gets worse chances are it more clutch or crank thrust bearing wear.

[kraanc]

It would be an idea to check the gearbox oil level.


How do you check gearbox oil level? ah :shrug:

[Mr_Shed]

From under the car with the under tray off you will find two plugs at rear of gearbox. Undo top one( it will be tight so use good fitting socket). The level is correct if it 2-4 mm below bottom of plug with car level.