The 9 and 10 have the suffix a30 on 3rd and 5h gear on the mainshaft The 11 and 12 have the suffix a50 3 and 5 on the main shaft. Does anyone know if they are physically different? The part number is not superceded. Seems all others are the same. However the center shift fork is. I'm hoping maybe the new part number may have longer dogs.