Based on your report OP, I think you may looking at an expensive fix. But no way to know for sure via the internet, you’ll need someone skilled w/the Jeep in front of them to know for sure. On an optimistic note, there are many things that can cause knocking sounds which aren’t expensive to fix. Exhaust leaks for example make quite a racket, most owners refer to them as firecrackers sounds, but they can sound like knocking too. Exhaust leaks often aren’t overly expensive to fix. No need to guess, take it to the local auto repair shop and get a proper diagnosis. Then you’ll know for sure where you stand. Keep your fingers crossed for an exhaust leak … 