So I was watching Eljay's review on the Toa Metru and he said that he couldn't find a fix for the gear function problem, however, I found out a way not too long ago after I got Toa Iruini, and thought since Eljay will be reviewing the Hagah who have the same body builds, it would be a good time to share it.
It is actually the same as the fix for the Mata gear function, except it uses the larger gear that can be found on the backs of the Toa Mata.
This won't work for the Toa Metru, but it will if you move the axle in their torsos one hole down.
Now you can high-five Hewkii like never before!:
Hope this helped, can't wait until the Toa Hagah review!