When I replaced the knob on my transmission (standard, though), rather than try to yank off the old knob the mechanic took a large pair of pliers/vice grips and squeezed the knob until it cracked and came right off. Putting the new knob on was much easier since it just snapped in...
I'm not sure if your knob is similar, but it worked for me!
Good luck... don't break anything...