I was getting to grinding noises from my Zenmuse gimbal and while trying to trace the cause I noticed if I placed my finger lightly on cap at the back of each axis. I could feel abnormal vibration from one which was the source of the noise. So I tightened the three screws remounted the go pro and hey presto it cured and I have a silent gimbal again which doesn't flick about during filming. Here's a little video I made showing the adjustments. I hope it helps others
Sadly my video skills are poor so the video Is rather amateurish but you'll get the idea