Cub.... that just answered my question too, I think.
Mine will jump and jerk when raising or lowering a little at a time. It's OK full lower to full raise and the other way around.
I got some seat time the other day till I broke the pitman arm. Once you get the hang of a sickle bar, they are cool to work with. My buddy grabbed it (pitman) out of the back of my truck yesterday and said I'll have a new one and some spares soon.