27-09-2019, 05:47 PM
I have got a couple of gearboxes that I think have the same problem - they are both noisy, particularly noticeable when the engine is idling and the gearbox in neutral. The noise disappears if the clutch is pressed. Both gearboxes are 4 speed 2 syn with Nippy close ratio gears, one original and the other modified to close ratio.
The gearboxes have shown the same symptoms on two different engines so I don't think the problem is engine or flywheel related. The only things turning in the gearbox when in neutral are the first motion shaft and the lay-shaft. The first motion shaft and inter-shaft bearings are both in good condition so I am thinking it must be related to the lay-shaft.
I have measured the lay-shaft end float on one box as 20 thou which is a lot more than recommended but the lay-shaft bearings look in reasonable condition. Could the end float be the cause of the noise or is there something else that I should be looking at?
I have an MPEG 4 audio file of the noise - does anyone know if it is possible to upload it here?
The gearboxes have shown the same symptoms on two different engines so I don't think the problem is engine or flywheel related. The only things turning in the gearbox when in neutral are the first motion shaft and the lay-shaft. The first motion shaft and inter-shaft bearings are both in good condition so I am thinking it must be related to the lay-shaft.
I have measured the lay-shaft end float on one box as 20 thou which is a lot more than recommended but the lay-shaft bearings look in reasonable condition. Could the end float be the cause of the noise or is there something else that I should be looking at?
I have an MPEG 4 audio file of the noise - does anyone know if it is possible to upload it here?