Andrea, an observation or two that I hope might be of help to you. (Remember, as always, I'm only a hobbyist and these are just suggestions.)
According to my references, the "48th Armored Infantry Regiment" was redesignated the "48th Armored Infantry Battalion" at Fort Benning, GA on 20 Sept 1943. I think this distinction might be important as you continue your search.
The ABMC database lists 120 entires for 48th AIB. In case you have not already accessed it, do a search for "48" at this web page: