I have a sump pump and it pumps out the water ok, but when the motor shuts off, it goes thump, thump. sometimes it does it 4 or 5 times. I don't know why its doing this. its pumping the water out of the hole in the house and i can see it outside in the ditch where it empties out. Someone thought it might be the in-take valve? Do sump pumps have those? I'm stumped on now to fix my sump pump. Help!