Noisy gearboxes

[daveg]

Thanks to all  for taking the time to share your experience.

Ian - I will remove the misplaced synchro cone and examine the toothed bore. Although not in the right position it is firmly fixed so hopefully another couple of mm of engagement will help. What temperature should I heat it to? The lay shaft looks the most worn component I have examined so it is re-assuring you don't think it is too bad, despite the grooving it turns smoothly in its bearings and has very little slack. If the lay shaft cluster has been modified perhaps what I thought was an original Nippy gearbox has had a close ratio conversion - this would explain why I have the same problem on both gearboxes. 

Bob - not sure "cluster" counted teeth all gears:

1st motion shaft gear 21, lay shaft input 30
1st gear 30, lay shaft 11
2nd gear 26, lay shaft 25
3rd gear 33, lay shaft 20

This gives ratios of 1st 2.896, 2nd 2.357 and third 1.486 which match the sports 4 speed gearbox ratios listed in the A7 companion.

Terry - thanks for the diagram of the bearing removal tool - I am going to need one of those.