does sound like case not inserted properly.make sure to put drop of oil on case before inserting.left hand rear there is a small funny looking plate that can move,that should be over case and in such a way that it still allow 1mm movement of case,right front there is a spring loaded plate that keep case from turning,gap off ,5mm is needed for thread to pass thru.after inserting first turn handwheel couple off times to ensure case is seated properly and thread can pass easily round case.hope it make sense
johan, September 2013
