Took everything apart down to the discharge housing assembly but found nothing wrong. Unscrewed discharge housing and found rivet had come off of inner plate. Plate was resting on the impeller. Attempted to epoxy plate back on but didn't last through one cycle. Replaced housing assembly and impeller (not broken but just for good measure). O-ring for housing out of stock. Found similar one used for inline water filter at hardware store. O-ring not exact size but stretched it to fit. Worked fine.