Ok I stand corrected I thought remembered a jeep. Maybe I am unduly influenced by the movie.
You may be thinking of General Walton Walker, 8th Army commander in the first year of the Korean War. He was killed in a roll over jeep accident.
He was succeeded by one of the greatest commanders in US history, Matthew Ridgeway, who went on to become UN Supreme commander when MacArthur was fired by Truman..
It was a staff car in the movie, too.