Small Engines (Lawn Mowers, etc.): drive problem with a 18.5 hp Carftsman riding lawn mower, craftsman lt2000, woodruff key

Question
I have a 3 year old Craftsman LT2000 42 inch, 18.5 riding lawn mower.  Recently while mowing it just stopped moving.  Engine runs fine, but the mower will not move in drive or reverse.  Drive belt looks ok, but the clutch now feels a little loose. I tried getting it to go without using the clutch, nothing happens.  What do you think is the problem?

Answer
If this is a Hydro check your bypass valve.  This is the valve you pull when you want to push the tractor.  Make sure it is closed tight.  If this is your drive inspect the drive system from the outside in.  Check the belt, pulley, and the Woodruff key on the input shaft.  Whether it is a gear drive or a Hydro linkage between the clutch or motion control lever and the transmission is critical.  The linkage to move freely and fully engage the transmission.  Be sure to check the brake and brake pad for damage or out of adjustment.  If it is nothing on the outside it will be internal broken key broken gear something along those lines because it happened suddenly.  Next the transmission would have to be removed and disassembled.  I hope this information helps.