Empire and Honor by W.E.B. Griffin and William E. Butterworth

Empire and Honor (Honor Bound) - Its October 1945 and the OSS has been closed down, but Cletus Frade and his associates in Argentina are on special assignment to the President. Their mission is to help certain Germans to immigrate to Argentina to escape the the wrath of the Russians.  They also are detailed to find certain U-boats believed to carry high ranking Nazis, uranium, and money.
     One of the U-boats that the OSS is looking for turns up in Argentina, but Frade and his crew don't know where.
     Because he speaks German fluently, Second Lieutenant James D. Cronley Jr. has been assigned to the Army CIC to help repatriate Germans who have fled Germany during the war.  He happens upon the widow of one of the Germans who have helped the Americans.