Tractor Won't Move!?

I have a John Deere 5300. Was workig it this morning, drivign on road in range C, as pulling into driveway, I depressed clutch, shifted to range b and let out on clutch, heard a metallic something spinning like sound and then silence, tractor won't move, Clutch pedal depresses and realese freely, all gear shifts move freely no grinding with engine running? As if clutch is stuck depressed. Suspect clutch issues or broken main shaft? With engine running I depress and release clutch pedal, no engine load, as if clutch is not engaging, or if it is there's no load there.

Brad
February 2013