Place beef roast in slow cooker. Sprinkle onion soup mix on top. Add mushroom soup and garlic and smear on top of roast. Add beef broth.
Put lid on crockpot and cook 9 to 10 hours on LOW.
Remove lid and shred beef using 2 forks. Add noodles and enough water to mostly submerge the noodles. I try to use as little water as possible because I don't want to water down the flavor. It's ok if some of the noodles are sticking slightly out of the liquid. There is enough moisture and condensation in the crock pot to cook them thoroughly.
Cook for 1 hour. Check for seasoning and add salt and pepper to taste.
Notes
Some people prefer to cook the noodles separately and stir them in at the end.Also, some people have found that their noodles are not fully cooked after 1 hour on LOW. Depending on your slow cooker, you may need to cook the noodles for as long as 2 hours.Nutritional info is provided as an estimate only and will vary based on brands of products used. Not to be used for specific dietary needs.