OK, so looking at it, it seems that the major thingsa holding it on, is the big yellow clamps on the axle tubes. Also its hard to see, but it may have brackets on the where the axle tubes bolt to the trans. I would not worry about that PTO housing behind the tranny for now, looks like the shaft will slip right out of there.
You have a full on shot of it, and the tractor??
I assume it will be REAL heavy, so you will want to get as much off of the main trancher frame before you go unbolting it.
My biggest concern is the section bolted to the rear of tractor. The second picture is from the bottom looking up. I don't know if there is a trick to the spline or shaft that I assume is inside. I will post more pictures tomorrow, too dark now. Thanks for looking.
I am still a little foggy on what you are trying to remove. Using my knowledge of my Ditch Witch trencher, the PTO shaft runs back into a gearbox that powers the cutting stinger. If you are trying to work from the back going in, after removing the stinger, the gearbox should present a way to remove it. Let me know what you are trying to acheive and send a few general pics to help as I am not familiar with that brand of machine.