The M189 transmission has an odd bell housing (front pump cover). Nothing else from the 60s is like it.
The innards are "standardized" after some early year, I forget which one; and anything rebuilt would in theory have gotten standardized if it didn't start that way. Not sure if that standardization applies to the input shaft itself though. That requires time with the EPC open or the old paper parts book (or fiche?) to confirm.
-CTH
PS. If three transmissions show up, I'm the next guy in line for one.
