On waxed paper, sprinkle beef with 2 tablespoons flour, salt and pepper; toss to coat. In 10-inch skillet, heat oil over medium-high heat. Add coated beef; cook and stir 4 to 6 minutes or until browned, stirring occasionally.
In 4- to 6-quart slow cooker, layer potatoes, onions and carrots. Add browned beef; sprinkle with any remaining flour mixture. Top with gravy and tomatoes.
Cover; cook on Low heat setting 8 to 10 hours.
Before serving, in small bowl, blend 3 tablespoons flour with water. Stir into stew. Increase heat setting to High; cover and cook 10 minutes longer or until thickened.