[LM3929]

First of all you should let us know what type of unit you have, that might help a bit.

I helped a friend drop his out a 5th wheel but it doesn't look a lot different that doing my TT.

you will need to remove the plastic undercarrage liner as much as needed to get at the tank retaining straps and disconnect and cover/seal the larger 3" ? discharge (4 bolts change the seals while you have a chance).

Lower one edge of the tank to see if there is a large or small inlet you probably will have to remove the toilet and flange or if everything is glued together cut the plastic pipe with a saw leaving enough of the pipe stub to be able to glue on a coupler.

Lorne M.