Clutch/ Gearbox noise on a series 1 4.2

[Jen]

Hi guys

I have a bearing noise from the gearbox / clutch which disappears when the clutch pedal is depressed

I would normally suspect the thrust bearing but i have read the car is fitted with a carbon thrust bearing and I`m not sure of the construction of these

I also notes quite a lot of swarf on the magnetic gearbox drain plug when I changed the gearbox oil

The box has no other apparent issue

All suggestions welcome

Thanks

Regards

Jen

[christopher storey]

When you say " a bearing noise" what type of noise is it? And are you referring to hearing this noise with the car stationary and the engine idling ? - if so, this is not unusual , particularly when the oil is not hot and there is quite a lot of oil drag on the gear trains. If it disappears when you press the pedal it is unlikely to be the release bearing - BTW some cars have had replacement ballrace bearings fitted, so not all have carbon thrusts. Have you checked that you have the correct oil in the box - it should be 75/90 EP and NOT straight oil in a 4.2 - some workshop manuals contain an error and the wrong oil is put in as a result . Also, does the noise appear either under load or on the overrun when rolling ? If neither of these, there is probably not much to worry about

[tinworm]

Could be first motion shaft bearing starting to go - when you push the clutch pedal down the gearbox mainshaft stops turning that's why it goes quiet - they will go on quite a long time before you have to do anything.

regards Barrie

[Jen]

Thanks guys

Lots of food for thought there, I will have a look the week end and get back on my findings

Thanks again Jen

[Candellara]

Hi guys

I have a bearing noise from the gearbox / clutch which disappears when the clutch pedal is depressed

I would normally suspect the thrust bearing but i have read the car is fitted with a carbon thrust bearing and I`m not sure of the construction of these

I also notes quite a lot of swarf on the magnetic gearbox drain plug when I changed the gearbox oil

The box has no other apparent issue

All suggestions welcome

Thanks

Regards

Jen

Jen

My S2 4.2 does the same - when hot. I've been told by my XK specialist that it's not uncommon on these engines due to the carbon bearing

They assured me it's nothing to be unduly concerned about

[38E]

A carbon thrust is hardly going to make a "bearing noise". It's just a smooth carbon ring running against a smooth steel thrust plate.

So long as the gearbox is in neutral and the clutch is engaged, you'll have the first motion shaft and the layshaft spinning when the engine runs.

The first motion bearing would probably make a rumbling type noise if it was bad whereas the layshaft bearings would make more of a whine. Still probably not much to worry about unless the noise gets very loud.

[5speeds]

This is a common issue, and the cause is always thought to be bearings. If you have ever worked on these transmissions in any sort of volume, you would know that the main bearings RARELY go bad. People grind reverse often. When you grind reverse enough times you bang up the reverse idler gear and roll the edges over. The reverse idler is always in mesh with the countergear and the banged up portion of those teeth are riding against the countergear in neutral and all other gears... except reverse.

So.... often times a person will have a 4 speed rebuilt with all new bearings and a new layshaft only to still have this rumbling noise.

The cure is simply to deburr the idler gear with a small die grinder. I don't know if new idlers are available..

[Candellara]

To update this, my engine & gearbox is now out and the problem - one carbon pad in about 6 pieces with half of it completely missing

A total new clutch to replace the paddle clutch that's fitted currently