I just replaced the sink flange that is connected to the garbage disposal, and the disposal is leaking upon reassembly. It does not appear to be from the flange, on which I used plumbers putty, but seems instead to be at the top of the disposal... as circled in the photo. It was darn hard getting that thing back up in there, but it seemed to be all done correctly. It is on tight. Is there something I am doing wrong, something that needs replacing, or is the disposal history?