My Kubota GST L3010 recently started acting like the clutch is slipping. If I am in any gear above 2nd, and I go into a pile of dirt, the engine does not bog down and the tires don't spin, it just stops. But if I drop to 1st or 2nd gear, the tires will spin going into a load. It used to either spin or stall the motor out if you were in a higher gear. I'm trying to figure out what the issue is. Being a GST, there shouldn't be a direct clutch drive line - right?