The DI motors pto are NOT threaded, they are pressed on, so don't try to unscrew since you'll cause major damage. Take the 6 bolts out and remove the shaft, take flywheel bolt out and then all you need is a puller, most standard heavy duty 3 bolt automotive pullers will work.
Even for the threaded ones, I don't recommend using an impeller tool. It's just too easy to rip out the splines. The best method is to use a large pipe wrench on the outer shaft and a 3' breaker pipe(watch out for the grease zerk). It will put teeth marks in the pto but you won't strip out your threads.