[AlecS]

dandaman,

What you are seeing here is run-in of the ceramic coating. This coating will often discolor as you have shown, and this is a normal occurrence that does not affect the gear. The profile of the gear is still in excellent condition. As others have said, these gears, and ones similar to them routinely run full seasons with little to no wear.

That being said, all WCP/VEXpro gearboxes should be greased before use, as noted in the user manuals. Failure to do so will result in excessive wear of the gears. White lithium grease, available at almost all hardware stores is an excellent choice for this. For the WCP gearboxes, you can also use a dry grease, (Mcmaster #8710T35), which is a less messy alternative to the white lithium.

Let us know if you have any other questions