912 GEAR BOX

Yes, when I throttled back in flight I had vibration that turn out to be worn splines on the prop shaft. It was a very expensive repair!

A gearbox can wear abnormally for different reasons. i.e. low idle rpms or never carb balancing or poor prop balance.

Once wear has set in then it can easily cause some vibration. Then it's time to send it in.

p.s.

Just getting a dynamic prop balance can help many vibrations and wear,.

Hello Kevin

Not shimming the gearbox can create this issue.  If this gearbox has an overload clutch watch the friction settings never get to the minimum values.  Additionally it may be a mismatch between the dog gear and the large driven gear on the propshaft.  If they are not showing equal pressure wear on the ramps it suggests that both must be changed.  Failure of this pressure to be equal can cause a lot of vibration which wears everything inside.

I fully agree with Roger in that you should always do a dynamic balance to extend the life and reduce wear/vibration.

Cheers