My brand new Crusader had no drain rod for galley grey tank which I discovered first night out.
The monitor showed fresh water, grey tank, galley tank, black tank and battery yet I only had pull rods for Black and grey tanks. ( 1 rod missing )
What I found was a hole in the frame near the other two rods. It required the purchase of a new rod which went through the hole and screwed into the hidden discharge valve for the galley holding tank.
It appears that the original rod had unscrewed itself and disappeared during delivery to the dealer.
This might be an answer to your problem