I am working on a transmission and need to create a shaft with a gear worked from the shaft (not mounted afterwards). The shaft is made after the gear is created, in the same part.

I put the gears and the gearshafts  together in the transmission assembly, and save the work. But next time i open the assembly, alle gears and gearshafts  have errors and are replaced with "spur gear". Mates are messed up as well.

How do i fix this problem?

Note: when the gears and gearshafts parts are opened before opening the assembly, the problem does not occour and mates works with no erros.