My dishwasher (Frigidaire Model FDB2000RFC1) is making a loud clicking/cracking sound when the drain pump is active.
I dismantled the "drain pump assembly" part making the noise and the solenoid and paddle flaps looked fine. However when manually turning the flaps I could occasionally reproduce the slappy / crackling noise.
Upon further inspection, it was apparent that the seal the axel for the agitator had a small leak. I ordered a new piece and sure enough, the sound is gone!