Question about pic

I put too much tension on this tail gearbox because the tail boom wasn’t pushed into the main frame as much as it should have been. Because the belt had too much tension on it one of the bearings got hot and melted the belt tail gear. The arrow is pointing to where the tail belt gear in the gearbox should be it’s no longer there because when it melted I took it out. I was wondering where I could possibly get another tail belt gear to put back into the tail gearbox set. Also my manual doesn’t show this but I think I have seen this tail gear set with bearings above and below the belt where I have drawn the circles. Should I add two bearings in the gearbox?