Assuming this is a motor coupling for a Whirlpool direct drive model, you probably did not get the coupling installed correctly. Very common problem when diy'ers do this job. You must install each half of the coupling onto the motor shaft and transmission shaft far enough that the end of the center part of the coupling halves are even with the ends of those shafts. If you don't do that, there is too much lateral pressure on the motor shaft when you reinstall the motor. This can quickly lead to bearing failure in the motor.

Eric