Place the roast in a greased crock pot.
In a medium bowl, mix together the onion soup mix, au jus mix, beef broth and water. Pour mixture all over the roast. Cover crock pot with the lid.
Cook roast on Low heat for 9 to 10 hours OR cook on High heat for 6 to 7 hours. After it's finished cooking, carefully transfer hot roast to a cutting board. Remove any fat then shred.
Place desired amount of shredded beef in crusty hoagie buns. Top with sliced cheese. Set sandwiches on a baking sheet. Place under the broiler until cheese is all melted and buns are toasted. *Watch the sandwiches the entire time while they are under the broiler. They can burn fast!*Ladle the au jus gravy from the crock pot into small bowls. Dip your sandwiches in it and enjoy!