Season the chuck roast generously with salt and pepper on all sides.
Place the quartered onion, minced garlic, carrots, and potatoes in the bottom of the slow cooker.
Place the seasoned roast on top of the vegetables.
In a small bowl, whisk together Worcestershire sauce, beef broth, and dried thyme, then pour over the roast.
Cover and cook on low for 8 hours or high for 4-5 hours until the beef is fork-tender.
Remove roast and vegetables, slice or shred the beef, and serve with the cooking liquid spooned over top.