One of my 6055 has developed a vibration. What looks to have happened is the stainless shaft that the magnet prop assemble slides over has become loose. You are able to rock the shaft a little which I think is causing the vibration as well as the prop to rub on the shroud. I am thinking the pump is wore out and needs to be replaced. Is this the right course of action or is there something that can be done with this pump?