I'm sure that if there we two, there were others in the past who made the same mistake.
Kind of a reminder, when you take the cases apart, be aware that the differential and the gear cluster sort of naturally "nestle" in one half of the case (I don't remember which side), the other case half fits over the lot. Also be careful in removing the case, make sure no spacers, gears or other bits fall out as the case is lifted.