There was a major reorganization in 1901, during which the Artillery Corps was formed by consolidating all existing artillery units, coast and field. This proved impractical and brought about another major reorganization in 1907. 3d Field Artillery was one of the regiments created by the Reorganization of 1907.
The regiment was constituted in the Regular Army 25 January 1907. Organized 31 May 1907 from new and existing units with Headquarters at Fort Sam Houston, Texas. Assigned to 6th Division 17 November 1917. No overseas service during World War I. (Individual battalions inactivated and activated at various times between 1922 and 1940 for economic reasons.) Relieved from assignment to 6th Division and assigned to 5th Division 24 March 1923. Relieved from 5th Division and assigned to 6th Division January 1930. Relieved from 6th Division and assigned to 2d Cavalry Division September 1939. Reorganized and redesignated 3d Field Artillery Battalion January 1941. Reorganized and redesignated 3d Armored Field Artillery Battalion 14 July 1942, concurrently relieved from assignment to 2d Cavalry Division and assigned to 9th Armored Division. Served with division in Europe throughout the war.
All I can relate for certain is that the regiment was assigned to 6th Division (later redesignated 6th Infantry Division) during your Dad's service. Where he was stationed at any given time and other particulars depends on what battery and/or battalion he was assigned to.