You need a pto/impeller removal tool. I just went through removing PTO on my 720 and my 3 800’s. I used a big bench vise, and impeller/pto tool and a long breaker bar. LOTS of heat. Every time I removed each PTO the crank seal behind it was alway ruined. But I planned on replacing crank seals anyways. If you are planning to take the bottom case half off, you should just put new crank seals in anyways. Just for the sake of you already being there.