Hello all! Looking for some help here-what could be wrong on a 955 JD Compact when you push the PTO lever forward,and it acts like it engages but the PTO does not run and it almost kills the tractor? Is there another button or lever to push? I am trying to run the rear PTO shaft. The rear PTO shaft does not turn freely when I try to turnit by hand but the belly one does. Is there another lever to push or something? Thanks for any help!!!