Place flour in shallow dish. Add steaks, 1 or 2 at a time, and turn to coat completely. , In a skillet, cook steaks in oil until lightly browned on each side. Transfer to a 3-qt. slow cooker. Add the onion and 2 cups water. Cover and cook on low for 8 hours or until meat is tender. , In a bowl, whisk together gravy mixes with remaining water. Add to slow cooker; cook 30 minutes longer. Serve over mashed potatoes or noodles.