There is a height adjustment on the end of the add on casting that adjusts the enmeshment of the drive gear to the driven gear on the table. If it's too tight it will "jump". Good grease is a must. I use a synthetic water proof grease that has Teflon in it. I've seen first hand how this stuff is incredible at hanging in there when other greases quit. It's also imperative that your ways are lubed. This is a hassle because all we've got is those little ball Oilers and really you should pump them up in several places on the travel IMHO and you can do that with the front but only close to the ends of travel in the back. Use only good way oil, not motor oil, makes a HUGE difference. And lastly, when was the last time you pulled and cleaned your X&Y lead screws and their half nuts? This is what made the biggest difference on my RF30. Once again good grease on them is the secret.