Hey Dennis,
I didn't pick up on this the first time I looked at your father's discharge paper but now I see he was National Guard before active army. For "Component" in box #5 is typed "NG", which of course stands for National Guard. Under "Remarks" in box #34 is typed "In state service NG of Illinois 4 Apr 40 to 4 Mar 41". This gives us the time frame of his National Guard service and also tells us whatever Guard unit he belonged to was activated to regular army service on 5 Mar 41. Armed with this knowledge we might be able to narrow it down to which unit he initially belonged to. Guard units were typically assigned to a infantry or artillery regiment etc., then placed with a division upon being called to active service. I did a quick google search for Illinois Guard units activated on 5 Mar 41, elements of the 33rd Infantry Division was what it mainly showed. That dog isn't gonna hunt though because the 33rd was deployed to the Pacific Theater of Operations. We do have this track we can follow. I'll keep looking and maybe Gary can pick up the scent, see if we can find this bird!
Randy
I discovered two more photos of my father, one standing in front of what looks like an ambulance and the other behind a sign for the 108 Medical Unit, which, as you point out, was part of the 33rd Infantry Division.