Man, how did you get pitman arm off that old box? I'm swapping to the RNR box today. Tried like hell and was just starting to break pitman arm puller! Finally just took the old box off so that could get the swap done while my son was here to help. Still have to get the pitman arm off the old box which is gonna be fun now that it's not held in place by the frame :(

 

The POS gets really stuck on there not gonna lie, luckily the pitman arm puller worked for me (if it didnt id be in a very similar place as you) but I did see some youtube videos where they had them break trying to pull it out. Taking it off the frame definitely makes it more challenging. Maybe try running it over some heat or WD40 and see if thatll give you enough room to work with on pulling out the arm with the puller again if its not damaged. I wouldnt say hit it with a hammer (or use brute force in general) as it could damage the threads needed to connect to your sector shaft or just damage the arm in general, but maybe try it with a rubber hammer if worst comes to worst. Although fortunately a pitman arm isnt the most expensive thing out there. But I hope it goes well and youre able to get the jeep driving again.