Place meat in a large bowl; season all over with salt and pepper and coat in flour. Warm 2 Tbsp. oil in a skillet over medium-high heat. Fry half of meat until brown all over, about 4 minutes; place cubes in a slow cooker. Warm remaining 1 Tbsp. oil in skillet, fry remaining meat and place in slow cooker.
Add onions and carrots to skillet and cook, stirring often, for 2 minutes. Add garlic; cook for 1 minute longer. Add onion mixture to slow cooker.
Pour vinegar and wine into skillet, bring to a boil and then add mixture to slow cooker. Season mixture with salt, pepper and thyme; add bay leaf. Cover and cook on low heat until meat is tender, 5 to 6 hours. Remove bay leaf and serve hot.