Fristly , just tell what i experienced.
When my one way gear was easy meshed , i found that two parts were need to change. They are Gear Box and the bended main shaft. (Am i right?)
For the gear box , the location of the small gear (for the 2 small bearing) , it was easy lossen after a period of time....e.g. 2-3 months . There will have a small gap and you can move the shaft cup easily.(Left , right , up and down....360 degree are lossen , not fit with bearings)
And then , if the main shaft was bended , it will have heavy virbration when it rotating. It makes the small gear easy meshed with one way gear.
any other reason?