I've done this a few times before.... First, ignore the instructions to use a screwdriver to pry off the old drive coupler. The coupler is only held on by left handed threads that have tightened. Use a rubber mallet to give the rubber coupler a hit along the outer edge with a clockwise spin. It normally only takes a few blows for the coupler to break loose and spin off. A good edge hit rubber-on-rubber will break it loose. Then it just spins itself off. The new coupler screws on counter-clockwise.