I have a Craftsman LT 2000 18HP 42" cut, manual transmission. It is a 2004 and it has very low hours (40). I was cutting with it and it just stopped, the engine kept running just fine, the blades kept spinning but it was like it was in neutral. It can put it in any gear but nothing happens. Everything works great except that it seems like the clutch is pushed in all the time. I have visually checked all obvious parts.

Have you checked the drive belt?

Check The Drive Belt, If It Is There, Is It Routed Correctly, Or Did It Jump Off A Pulley, Sounds Like The Belt May Have Jumped Off, And Yes The Hardest To See, The Trans Pulley And Running On The Shaft, Good Luck.

I would look and see if the lever didn't accidentally move out of position on the back of the mower, that will make it seem its stuck in nuetral