14-07-2020, 08:39 AM
Thanks for the thoughts and tips - duly noted and absorbed.
Looking at it in more detail last night, it seems that what happened is that the 2nd gear synchroniser effectively 'hung up' on the 2nd gear syncro cone so that when 1st gear was selected, instead of the 2nd synchroniser moving away from the syncro cone and sliding along the third motion shaft with the first gear wheel, it stayed where it was and the first gear wheel slid along the 2nd synchroniser instead... exposing the balls and springs....
I can't really see any reason why it might have done that and there is no obvious wear, lash or play that I can detect in the box - so the reason for the failure is still a mystery. Nothing else in the oil to suggest any other components are broken etc. The only thing I can think is that the internal ball detent grooves in the first gear wheel (into which the 2nd gear synchroniser balls engage) have worn sufficiently or the balls/springs have worn enough that the gear wheel didn't grip the synchroniser hard enough to pull it along the 3rd motion shaft when I selected first..... but I'm really not sure...
Looking at it in more detail last night, it seems that what happened is that the 2nd gear synchroniser effectively 'hung up' on the 2nd gear syncro cone so that when 1st gear was selected, instead of the 2nd synchroniser moving away from the syncro cone and sliding along the third motion shaft with the first gear wheel, it stayed where it was and the first gear wheel slid along the 2nd synchroniser instead... exposing the balls and springs....
I can't really see any reason why it might have done that and there is no obvious wear, lash or play that I can detect in the box - so the reason for the failure is still a mystery. Nothing else in the oil to suggest any other components are broken etc. The only thing I can think is that the internal ball detent grooves in the first gear wheel (into which the 2nd gear synchroniser balls engage) have worn sufficiently or the balls/springs have worn enough that the gear wheel didn't grip the synchroniser hard enough to pull it along the 3rd motion shaft when I selected first..... but I'm really not sure...