Where is the black tank

My DW went camping with just water and electrcial hookups. Didn't have Sewer hose hookup. So we tried the shower out and by taking Navy showers still filled up the gray water tank. Went to leave the camp ground and needed to empty the toilet. So I thought the TM had a black water tank. So since we ever pulled the leveler to empty the the toilet I figure we had plenty of space to rinse the toilet out. But the gray tank was already full. So it seems the toilet emptys into the gray tank? Becuase the black water in the toilet wouldn't empty out all the way. Had to use my toilet buddy to empty the gray water to make room to empty the toilet the rest of the way. Then I had to stop at the dump station to empty the tank the rest of the way.

I really thought the TM had both gray and black tanks. This is a problem when leaving as we have to open the TM back up at the dump station to clear the toilet. Any sugestions?