I pulled the lower unit to change the impeller and when I went back to install the lower I noticed an old backing plate from the flappers laying on the ground. So I pulled the top half and risers to check for more pieces which I found none but changed the flappers anyway. I put the two halves back together off the boat then installed the drive. After moving the shifter back to neutral I can still pull the drive off. It looks as if my shift cable is not moving the shift arm while the drive is mounted. If I pull the drive off the shift arm moves as it’s supposed to. Does this sound like cable has broken through the sheath or is there a way of messing up the shift rod adjustment when I was doing the water pump?