Yes, there is a thread....
Here.
I wish it was on here, but it isn't.
Brent, you can use the hole in the bottom as the suction (drain hole) and either add the return in the top, or use a top cover off a Lo-Boy. Look the thread over, this guy did an awesome job.
I wouldn't use this set-up for a loader, but that's my opinion. I think it would be really slow. Plenty of pressure, just not a lot of flow. If I was doing a loader, I'd use a lot bigger of a pump. More than likely ran off the front PTO.