I was doing soybeans this particular time but it slips in corn and wheat as well all fairly dry when harvested. Grease was the first suspicion but after getting it cleaned up nothing changed, his other machine is a 98 2388, same extensions more hours and the only time it slips is when you push too hard in good corn. This can be really aggravating because the separator can't turn on until you unload and it never happens in a convenient location.