Noiseboy-
That point about lightning strike damage to a main rotor gearbox is interesting. There are a couple way lightning strikes can damage main or tail rotor gearboxes.
Rotor blade lightning strike damage can produce sufficient dynamic imbalance force to damage mast bearings or even load bearing housing structures. I believe this occurred with an AS332 TR gearbox a few years back.
If the electrical bonding devices of a helicopter rotor system are poorly maintained and not performing properly, the next best electrically conductive path between the rotor and airframe are often the contacts between the rollers and races of the gearbox bearings. This can produce arcing at the very small roller/race contact areas, and pitting of the race surfaces.
Lightning strikes to turbine engine compressor blades occasionally cause damage to the shaft bearings. Here is an
interesting report of one such incident.