To put a QPAUT back on its socket first plug it, then close the top of the machine then turn it then screw the module. Then go back inside and push the shaft back in. Remember the original position. It should go smoothly if in the right position. there is a foolproof notch.
Once it is correctly positioned inside the selector check and change the power positions to make sure everything is ok, it should feel that the selector is actuated. then screw the allen screw of the shaft blocker so the shaft won't get out accidentally.