I had the same thing happen to the plastic gear carrier on mine too, replaced with the alloy one, not cheap hey. I was lucky and was just warming her up when it happened and didnt damage the gears. I slapped some greese in the bearings before even fitting the new one. Did you ever get a run with the trenchers on? I had them fitted up to try out and the gear carrier gave out within a min, havent had her out to give it a propper run yet...