I run a '99 Durango box on my YJ, I believe there is no snow-plow option in '99 but there is for the '98.
There's a trick to removing the pitman arm easily. Tighten the puller and, using a 3 lb sledge, hit the side of the arm where it attaches to the steering box at a 90* angle to the steering shaft. Tighten, hit, repeat. The hammer blow temporarily egg-shapes the pitman arm hole and helps it pop right off. Same method works great for ball joints and TRE's.