With the injection pump and intake off of my 6.5, I wanted to clear the valley drain that obviously stopped up and ruined my pump. But I can't locate it at the back of the valley. Looking at the left rear of the engine near the bellhousing/transmission, I found about a 1/4" hole I assumed was the exit drain. I tried to clean it out but quickly realized it has a metal plug in it. I verified it with a mirror. So my question is do they all have a drain?