After 71,000 miles my sunroof went belly up. When I took it apart I expected to find the typical stripped plastic gear but instead the black plastic cover that provides bearing support for the plastic gear had shattered. The gear itself, looks surprisingly good.

Two questions:

1. Anybody know why the cover disintegrated? I've read a lot of posts on failed sunroofs and never saw one with this problem.

2. Anybody have a cover from a bad motor they'd sell me?

Thanks for any replies