Dishwasher Hums during wash cycle

Dishwasher starting making loud noises during wash cycle - still cleaned dishes. After a while, when I started it, it would fill then start to hum during wash cycle like the motor was shot. I read lots post and took dishwasher apart. Chopper blade was bent. Fixed the chopper blade and cleaned everything, put it back together - it worked for about 2 minutes…then humming came back. I am thinking I need to order a new chopper blade and [SIZE=2]Circulation pump motor with volute, shaft seal and impeller. My question is how easy is this to install? The chopper blade I can do - I am concerned about motor. Also would I need to order any other parts? Should I fix this or just get a new dishwasher for $250? Any help is appreciated! Thanks. [/SIZE]