Need help with N-14

I have an International 9300 which I use to haul grain off the farm and also move equipment. There was a small oil leak from a rectangular plate which is held in place by six bolts/studs on the left side of the engine block behind and above the starter. Thinking it was an inspection plate of some sort, I removed the bolts with the intention of replacing the gasket, or the plate itself, if required. But there is something attached to the plate inside the engine and I fear I now have a much more imposing task in front of me. Can someone clue me in to what this plate is, what it's attached to, and what I'm looking at in regards to getting the truck running again? Thanks in advance.

 

Thanks so much for the feedback. I sure wish I had came here asking questions BEFORE I removed the bolts and tried to get plate off. No excuses really with the internet being what it is. One other question...what should be considered as normal oil pressure with an N-14? At idle speed, it's only about 5 lbs and runs about 25-30 lbs in road gear. This seems low to me but the truck doesn't use any oil, nor does it smoke.