Place beef in a large bowl; sprinkle with flour, tossing well to coat. Place beef mixture, carrot, onions, mushrooms, and garlic in an electric slow cooker. Combine beef broth and next 6 ingredients (through pepper); stir into beef mixture. Cover and cook on LOW for 8 hours.
Cook noodles according to package directions, omitting salt and fat. Serve beef mixture over noodles; sprinkle with thyme.