I have a Cub Cadet Z-Force 50 Zero Turn mower. It is jerking badly at low speeds, it is fine at high speed. I have changed the cavitation dampeners (also know as the "return to neutral cylinders) and it did not help at all! It also does not do this in reverse. I am wondering if anyone out there has ever had this problem and has figured out the problem And get this, I called MTD and asked them and no one there knew of this problem and had no answers for me, go figure ! Thanks, Thomas