Originally Posted by Karlos G

Release bearing is only under load when the clutch is depressed, and so also only whines when the clutch is depressed.



Then it is 100% the gearbox mate!!
Think about it..... What happens when you press the clutch.......... the engine is seperated/released from the gearbox and so the internals stop spinning, then when you lift off the clutch the gearbox internals start spinning again and you hear the noise!