Hello, I have a 2011 Thor/Four Winds Hurricane. I recently noticed that the drain flange (that holds the hair screen) seems to have separated and come off on the floor of the step in shower. I'm pretty sure it is supposed to be attached as one threaded piece that goes through the floor and hooks to the grey tank pvc pipe. It must've corroded through. Not sure if there is any damage under there. Is there an access anyone knows of for getting under the shower to assess and replace the drain flange? I haven't seen any obvious access panel anywhere so far. Thanks in advance for any help!