Spray 3 1/2- to 4-quart slow cooker with cooking spray. Remove fat from pork. Rub jerk seasoning over pork; sprinkle with thyme. Place pork in slow cooker. Sprinkle with onion. Pour cola over pork.
Cover; cook on low heat setting 8-10 hours.
Remove pork from slow cooler; reserve 1/2 cup juices. Use 2 forks to pull pork into shreds. Place pork in slow cooker. Stir in barbecue sauce and reserved juices. Increase hear setting to High. Cover; cooker 30-45 minutes or until thoroughly heated. Spoon filling into buns and enjoy.