Small Engines (Lawn Mowers, etc.): Troy-Bilt riding mower wont move, drive pulley, spring maintenance

Question
QUESTION: I hope I get this information correct because I am asking for my husband.  He did some spring maintenance to my mom's Troy-Bilt mower, model J609.  Changed the oil, spark plugs, cleaned the deck and sharpened the blades.  He put everything back together but now the transmission won't engage, you can't put it in reverse or any other gear.  Can't even get it to move turned off and in neutral.  It worked fine before he started.  Any idea what might have happened?  This isn't the first time he's done maintenance on a mower but he is just stumped.
ANSWER:   Hello Leslie:

 Has He Checked the Shifter Linkage? Did He Put the Transaxle Linkage in a Bind when He Reattached the Deck? Please, I Require the Complete Model Numbers to Locate the Proper Manual and Better Assist you. Is this a 13AJ609H063, 2001 Model or a 13AJ609G766, 2004 or 2005 Model. Thanks.

 Respectfully

 John

---------- FOLLOW-UP ----------

QUESTION: Model is 13AJ609G766 2004.  The deck has not been put back on.  He didn't look at the linkage when he took it apart so he's not sure if it looks different now.  He said it looks ok.

Answer
 Hello Again Leslie:

 It Sounds like Something in the Drive System has Frozen or the Transaxle May have Broken a Pin. I'm Thinking a Frozen Pulley or Frozen Transaxle Brake Assembly. Go to this Addy http://www.buymtdonline.com/webapp/wcs/stores/servlet/BuyMTDOnline/index.jsp and Select Use Our Detailed Parts Finder Button on the Right. Then Select the OEM (Cub Cadet). Then Enter the Model Numbers and Click Search. Then Double Click on the Model in the Results Area. Now you can Select the Components of the Mower you Wish to View Online. Check the Brake Assembly (listed under the Differential) and Make Sure the Brake isn't Frozen to the Brake Disc. If this is Working Good, then Have your Husband Remove the Belt from the Transaxle Drive Pulley. If He can Turn the Transaxle Drive Pulley by Hand and shift the Transaxle; then have him Check the Variable Speed Pulley. Remove the Belt from around the Variable Speed Pulley and Move the Inner Pulley Sleeve. It Should Move Easily form Side to Side. If the Problem is Not Here, then have Him Follow the Pulley System and Check All the Pulleys and Idlers. If the Belt Tension is No Released on the Transaxle Drive Pulley, the the Transaxle will be Hard to Shift or Not Shift or Move. Make Sure All Connection Points are Lubricated with Spray or Grease as Required. Hope this Helps. I am here if you Require more Assistance. Let me know what Happens, Please. Thanks.

 Good Luck

 Respectfully

 John