Gearbox/Engine Rumble

[tour de frans]

Hello Adrian
For some reason,I was thinking you have a petrol Patrol.Correct me,its a 4.2 Diesel?
If so ,what clutch kit dit you fit? If it is not the OE kit,you will have this noise.On the diesels the crank ossilate on each power stroke.This vibration will amplify through the transmission,And a noise will come and go on differant rpm.
The clutch plate has springs in the centre.Those springs get rid of the vibration.Worn or the wrong springs in the plate will give a vibration noise on a diesel.But when you press on the clutch the noise will go away,because clutch release the gearbox from the engine.Lets say the clutch plate are wrong.Then the noise wil still go away when you press the clutch all the way.Once in gear and clutch released and you are on the move the noise will come back as you throttle.Reason for this,the clutchplate/driveplate,drive the engine power to the box and those wrong or worn springs will transfer the engin vibration through the driveplate into the box.It will make that bad noise until the rpm is high enough to go away.
Hope this help
Rdgs
Frans

[Adrianjvr]

Hi Frans, thanks for the reply. I fitted a Valeo clutch which the seller said Nissan use on their vehicles, but I cannot confirm. I do have a diesel and believe the noise you are describing is gear rattle which I do experience. Changing from a 75W85 synthetic oil to an EP90 has significantly reduced this noise though. The noise I am concerned about is when I push the clutch in all the way and rev the engine. The noise only appears at around 2100rpm, below this there is no noise. If I do this with the clutch out and in neutral there is no noise. Seems to be a harmonic. I see the old discoveries were fitted with a harmonic damper on the clutch pedal so I was thinking of getting hold of one of these to try. If it was a bearing I would have thought it would make a noise at all speeds. Cheers Adrian