[Jon K.]

If you are still experiencing these sounds, I would definitely take the gearboxes off and double check the gears. It's highly unlikely that you have managed to sheer teeth off the steel gears in the TB Mini, but this is the year of the strange failures.

A couple of quick questions:

Did you run the gearboxes in for about 30 minutes prior to greasing them?
Have you done any maintenance on the gearboxes this season?
-Running outside might have introduced a foreign contaminant into the gearbox, and it might be worth cleaning the gearboxes out and greasing them again after checking the teeth.
Have you checked the tightness of the screws holding the CIM motors on?