We have a GE Profile Water Softner Model # PNSF31Z01. The Rotor shaft broke (part # ws26x10002), I believe because the rotor did not turn as easily as necessary. When replacing, the gear will need to be pressed on. Should a press be used, how much pressure should be applied? When the rotor is installed but before the motor is mounted the rotor should be able to rotate. How easy should the rotor be to rotate; as very easy with one finger, easily turned by hand, requires firm grip to turn, require pair of pliers to turn, etc?