[Cecil]

Make sure they are put together correctly, this will cause a lot of noise if done improperly.

Take the box apart and look at the gears. On all of them, you will see a small raised part on one side of it right around the hole in the center. Make sure that each one of these bumps are pointed toward the OUTSIDE of the case. this spaces them out from the bearings and the walls, and will eliminate that grinding noise. I would highly recommend you check this before attempting to break them in, as this can cause a lot of wear on those gears.