squidd, the transaxle half's, top and bottom are basicly identical, same characteristics on both halfs. So I dont see any problems with flipping it up side down as far as lubercation goes. But if the grease get's thin, I could see the grease try to ooze out of the shifter and input shafts. The transaxle came with thick grease and I'm gonna continue to use thick grease, if grease leaking out of the shafts become a problem, I'll deal with it then. It's going to see very light use, a 40-60lb kid over-driven to a mild 10mph.
TheMowinCuban, There are a few reason's why I did'nt go the jack shaft route. Space, it's very short and there is hardly enough room with out one. It need's to be as simple as possible to keep the weight down, the lighter the safer. And from my experience the less complacated I can make it, the less that can go wrong and fail.