Combine broth with spices, au jus concentrate and 2 packets salad dressing mix in a slow cooker.
Place roast in slow cooker, and pour Dales steak seasoning over the roast and the last packet of dressing mix
Chop onions and peppers into large pieces and cover roast with them.
Cover, and cook on Low for 10 to 12 hours, or on High for 4 to 5 hours. Half way through, turn the roast over. A half an hour before serving, shred meat with a fork and return to slow cooker and the juices.