KAWS850LQ1 Washer Won't agitate correctly

I replaced a broken coupler three months ago and it has worked fine until last week it stopped in mid-cycle - I could only hear a hum from the main control switch. Raised up the washer and turned the motor shaft by hand, and it made a big click. Washer worked OK after that until today when the agitator started spinning during the wash cycle instead of normal operation. Motor shaft when turned either direction spins basket, but not agitator. Any clues?