Boob-La...
Man you got that right! There seems to be a million different transaxles from a million different lawn tractors! A cross reference guide would be as thick as a NYC phone book!
Currently I'm leaning towards repair.. Someone suggested having the crack in the upper housing welded and after studying the manual you hooked me up with, I can see there are replaceable bushings at the ends of the axle. Assuming the gearing inside is all good, then having the housing welded would most likely be fairly inexpensive and the axle opening at the end of the housing, (which is current worn into an egg shape) could have any extra weld that came though rough ground out and then maybe finished smooth with 'liquid steel' and a new bushing installed.. As soon as the mood strikes me, I'm going to reread the manual on transaxle disassembly and take it apart.. I'll let you know how that goes.. Hey at the very worst, I'll end up with a bench covered with lots of parts.. right?
Roger