For the pork: Preheat the oven to 325 degrees F.
Rub the brown sugar, salt and pepper all over the pork. Place on a baking sheet, cover with a layer of parchment and then seal over the top with aluminum foil. Roast for 3 hours.
For the soy-da glaze: In a small saucepan, simmer the orange soda, soy sauce, crushed red pepper and garlic until reduced by half. Set aside.
Remove the pork from the oven, uncover and drain any liquid fat. Brush the soy-da glaze all over the pork and continue to roast, re-glazing every 30 minutes, until the pork is well browned, fork-tender and the meat pulls away from the bone (and registers 200 degrees F on an instant-read thermometer), 1 to 2 more hours. Transfer the pork to a large dish and let rest 20 minutes before pulling.
For even more crispiness, pull the meat, mix with the remaining glaze and broil on a baking sheet until extra crispy, 3 to 5 minutes!