30-07-2020, 07:07 PM
(This post was last modified: 30-07-2020, 07:09 PM by larrylamb11.)
I mused over the failure mode for some time and eventually concluded that the most probable cause was wear in the selector (plus normal wear and tear in the gear cluster). The wear in the selector allowed the 1st gear cog to wander beyond it's normal extreme on the 2nd gear synchroniser - either by being forced beyond it's limit by my action on the gear stick or through the torque of accelerating / decelerating in gear whilst I manoeuvred. At the same time the 2nd gear synchroniser reached the limit of it's travel, butting up against the end of the 'box. At this point the machined groove that retains the synchro balls in the first gear cog over-reached and jumped over the balls, allowing them to emerge 'box-side of the 1st gear cog. That caused the balls and springs to force the 2nd gear synchroniser onto the synchro cone and jam the box..... not completely locked solid, but tight enough that further progress is impossible without severe damage.
For me, the 1st gear cog was then jammed where it was as it hung up on one of the protruding springs.
As to whether a bush-side repair would be feasible, with some ingenuity and a fair amount of swearing I think it could be achieved within the car through the aperture left by whipping off the top cover.... It would be a matter of persuading the 2nd gear synchroniser back into the 1st gear cog or levering the 1st gear cog back over the synchroniser.... you'd have to extract any hung up springs etc. before attempting such a bush-fix, but it looks feasible and indeed Dave Mann reports doing almost exactly this some years ago when this failure beset him in Switzerland. A magnet on a stick would be invaluable in the toolkit to fish out balls and springs previously released into the oil and should prevent having to drain the oil from the 'box. You'd wreck the 'box pretty quickly if you found yourself unable to stop immediately or forced to carry on in 1st....
For me, the 1st gear cog was then jammed where it was as it hung up on one of the protruding springs.
As to whether a bush-side repair would be feasible, with some ingenuity and a fair amount of swearing I think it could be achieved within the car through the aperture left by whipping off the top cover.... It would be a matter of persuading the 2nd gear synchroniser back into the 1st gear cog or levering the 1st gear cog back over the synchroniser.... you'd have to extract any hung up springs etc. before attempting such a bush-fix, but it looks feasible and indeed Dave Mann reports doing almost exactly this some years ago when this failure beset him in Switzerland. A magnet on a stick would be invaluable in the toolkit to fish out balls and springs previously released into the oil and should prevent having to drain the oil from the 'box. You'd wreck the 'box pretty quickly if you found yourself unable to stop immediately or forced to carry on in 1st....