Dumb question #31039-

Is is normal to not be able to rotate by hand the outer (hollow) splined shaft going into the KM171 3-sp auto transaxle, or does this indicate some problem ? The inner shaft rotates easily.

Yes it is normal. This shaft is stationary and helps to support the weight of the torque converter and impeller case on the inside of the Torque converter. as the inner shaft slides into the inner impeller section of the torque .

Thank you--good news. I thought maybe this had something to do with the torque converter failure I experienced, where the splines for the inner trans shaft sheared off completely, but see now the outer splines here mate to something called the stator inside the TC, which is supposed to remain stationary, except how a one-way clutch lets it rotate. Fortunately AutoZone sells a reman TC for $150, so this isn't so bad--like a clutch job. Maybe historically there was some problem with these converters if the aftermarket has them like this. Those awesome 68 horses are just too much for it, apparently! But what I really would like to do is convert the car to a manual trans now that I have this one out, but haven't got a good line on the parts I would need. Anyone?

No its not uncommon. The TQ converter is like a closed drum. Inside are impellers , kinda like 2 inverse fan blades with a surrounded housing. As the TQ Converter spins the fluid surrounds the outside and the impellers help to center it back in to the center and thru the shaft , to the gear clutch drums. The TQ Converter also turns The transmission fluid pump. And in most cases, the splines on the inside of the TQ Converter that directly drive the pump that usually wear down over time , and cease to drive the pump. Ive seen this commonly after a series of years , anywhere between 4 years out of earlier KM series (F3A12 up to even F4A22) models The after market TQ i have seen all have cast steel inner splines to correct the issue of the earlier model TQ Converters .