Black tank flush?

[Huck]

I recently traveled for about 2 weeks without dumping my black tank.

When I dumped it yesterday I noticed that the black tank flush seems to be clogged.

I had this problem once before on another fifthwheel that I had, and I had to get to the place on the tank that the flush hose was attached and remove the spinning flush thing and clean it out to fix the problem.

Here is my Questions.
Has anybody else had this problem?
And if so, how did you get to the fitting on the tank to fix it?

I have a RE3, and after some examination I seem to think that the fitting is up under the bathroom/hallway floor with no way to get to it.

Any ideas??