mechanics of double helical gears

Hi:

according to the wikipedia page: https://en.wikipedia.org/wiki/Gear#Double_helical


the unstable and stable configuration would disassemble and correct the axial misalignment respectively.


I analyzed the forces on the meshing tooth and that doesn't seem to be the case.



http://postimg.org/image/62px4eacz/



what am i doing wrong?


thanks