Small Engines (Lawn Mowers, etc.): Problem with my Sears garden tractor, best guess, transmisson

Question
I have a Sears model 917.255960 with a 18 horse kohler engine. After blading snow at our house I parked the tractor to clean the snow off then I got back on the tractor to back it into the garage. I put the gear shit lever in the reverce position let out the clutch/ brake and it didn't go anywhere. I checked all the gears, same thing. The belt looks fine, seems to be doing all the right things, the transmisson seems to be going into gear when I shift. Is there a clutch there thats not doing it's thing any more, or what would be your best guess? In all the years I've had it this is a first.
Thanks
Dave

Answer
Hello Dave:

To View a Breakdown of this Unit Go to this Site Addy, http://www.searspartsdirect.com/partsdirect/index.action?sid=PSHx20080114x00001 and Enter the Model Numbers 917.255960 and Click Search. From this Page you can View Diagrams and Parts Lists for you Equipment Using the "View Sub Components" Section Near the Bottom Left. Are you Sure the Clutch Idler Pulley Bracket (#36) is Not Frozen and Not Tensioning the Belt Properly? The Only Time I have Seen this Problem is when the Clutch Idler Bracket Assy has Stopped Moving Properly Due to Icing. If you Hit a Snag or this Does Not Correct the Problem,  I am Here if You Require More Assistance. Hope this Helps. Let me Know What Happens, Please. Have a Happy Holiday Season and May the All Mighty Bless You and Yours. Be Safe and Happy. Thanks.

Good Luck

Respectfully

John

PS: I am Allowed to Answer 10 Questions a Day. If you See I am Maxxed Out, then Try Submitting your Question at or Just After 8pm EST (US). My New Day Starts then. Comments and Ratings are Greatly Appreciated. Thanks.

Respectfully

John