Place the thawed pork roast on a work space and sprinkle with the dried soup mix. Pat it on there all over the roast. Sprinkle generously with salt and pepper and place in the crock pot. In a medium bowl, whisk together the can of root beer and half a cup of barbecue sauce. Pour it over the roast. Place the lid on the crock pot and cook on low heat for 6 1/2 to 7 hours. Remove the roast from the crockpot and shred it with two forks. Then remove all but about a cup of the juice. Put the shredded pork in the crock pot with the cup of juice, then add the remaining 1 1/2 c. of barbecue sauce. Stir it into the meat and cook on high for 15 to 20 minutes to get the meat heated up.