I replaced a stripped mechanism in one of my fans this summer - the same scenario except no shipping charges. The reason for the damage is obviously common, and members should be alerted how to prevent stripping gears on their own fans.
If the fan lids sit closed for any length of time and through various weather conditions, the lid seals can stick. The automatic or manual modes of opening the lids will be stymied if the lid is stuck solid, and eventually the gears that drive the mechanism strip. The preventive move is to clean and treat the seal under the lid on the roof. There was a seal composite/manufacturer change sometime back that resulted in a less than optimum material. In addition to one new gear drive, Fantastic sent me new seals for both fans, with complete instructions. I treated the seals with the included and recommended Aerospace 303, but the lids still stuck down when I tried to open them a couple months later, in spite of the company's revamped seal composite.
I'd recommend regularly opening and closing the lids, esp. when a rig is in storage, just to keep the seal flexible and not taking a set. Probably wouldn't hurt to clean and treat with 303 a couple times a year, and practice not manually snugging down the lid too tightly on closure. Don't force a stuck lid to open either - that's a good way to strip the drive gear; you may have to go topside and give it a hand to crack the seal, or remove the screen and give the lid a little helping hand from inside. If you have your fans on automatic, and you aren't always present, stripped gears may be unavoidable without preemptive seal treatment efforts topside.
Joel