Cut roaster in half; rub with brown sugar. Place in a 5-qt slow cooker. Pour apple juice and soy sauce over roast. Sprinkle with salt and pepper. Cover and cook on low for 6-6 1/2 hrs or until meat is tender.
Remove roast; cover and let stand for 15 min. Meanwhile, strain cooking juices and return to slow cooker. Combine cornstarch and cold water until smooth; gradually stir into juices. Cover and cook on high for 15 min or until thickened. Slice pork and ser with gravy.