Black Tank ABS or HDPE or ???

[Tireman9]

Am doing more re-engineering on my 2008 Coachmen Freelander 2130QB. This time it is the black water holding tank. The dump valves were improperly oriented from the factory so they are both hard to operate and they are in direct line of shot for road debris from rear tires. If the valve doesn't clog because it is pointed down the valve gets broken from flying rocks etc.

So after removing the valves and large Ell fitting I am atempting to remove the pipe between the 3" valve and holding tank. It appears that Coachmen attempted to solvent weld a pipe union over the tank drain neck. They also had inserted a short piece of pipe inside the neck of the tank and are keeping it in place with a large hose clamp. There is also some kind of leak sealent where the ABS union fits to the tank neck.

The tank is black and the only identification I can see on it is "24 gal" "RV use" and the letters SA were cut by hand into the mold.

Is the tank ABS or some other plastic?

Acording to one very knowledgeable RV Service tech, the use of the inner tube and hose clamp indicates the tank is HDPE and the hose clamp is supposed to squeeze the neck around the inner pipe as you can't solvent weld HDPE to ABS. However the piece of the end of the tank neck seems to melt just like ABS.