All MX Machines are horrible on traction. You will even see ropes slip on inspection.. Just a horrible traction relation machine. Had one in Ft. Lauderdale that was Underslung (roped 2:1)and would lose traction at an intermediate floor and fault almost every trip. Think I remember this job had special ropes too. Lang Lay I believe. Don't remember if the MX's are all Lang Lay or not. Every Job I went on with MX traction problems all have had different solutions. Changing the Accel/Decel rate was always one solution. Wire brushing the ropes I never tried but could be another logical solution to a junk machine. Liquids and powders never seemed to work.. Double check your counterbalance too, if that is off the problem is much more constant. Even a couple hundred pounds can make a huge difference.