I just received the metal gears from caster (SKOP039) and they don't seem to fit.

I took my diff apart again and it seems like each time I do I find a pile of dirt inside along with a pile of gear fragments. I looked carefully at the case I didn't see any cracks at all. The diff was closed tightly all the way around.

Perhaps the dusty environment of my track is just too much for the b44.1 diff...