Pat chuck roast dry and season with salt and freshly ground black pepper all over. In a large skillet or dutch oven over high heat, heat oil until shimmering. Brown beef on all sides until a deep brown crust develops, about 7 to 10 minutes. Transfer beef to slow cooker.
In the same skillet, add carrots, onions, and potatoes and cook stirring occasionally, until vegetables begin to brown, about 5 minutes. Add garlic and cook until fragrant, about 30 seconds. Stir in red wine, deglaze pan by scraping up brown bits.
Add beef broth, tomato paste, thyme, bay leaf, 1 teaspoon salt and 1/2 teaspoon freshly ground black pepper and bring to a simmer. Transfer mixture to slow cooker. Cover slow cooker and cook on low until meat is fork-tender, about 5-8 hours. Remove beef and vegetables (discard bay leaf). Keep warm while making gravy.
To make the gravy, pour drippings into a bowl. Allow fat to rise to the top. Skim off fat and reserve 1/4 cup. In a large saucepan over low heat, pour in reserved fat. Whisk in flour and stir until mixture is bubbly. Set aside to cool.
Measure remaining meat juices and add water until it reaches 2 cups liquid. Add mixture to sauce pan, return to medium-high heat and bring to a boil, stirring constantly. Boil until mixture thickens, about 1 minute. Season to taste with salt and pepper. Transfer to a serving platter or serve the pot roast with vegetables right from the slow cooker.