Small Engines (Lawn Mowers, etc.): Craftsman Hydro Gear Transaxle, craftsman model, hello jerry

Question
I have a Craftsman Model# 917.273800.  The transaxle part number is 166768.  The tractor is about two years old and reverse seems to be slowing down more and more by the day. I can't totally tell if there has been a loss of speed in the forward speed but if I was to guess, then probably a little bit.  What would you suggest I try first, second, third to get the tractor back to original speeds.  Does the belt need replacing, do I need to tighten something?  I realize the transaxle is sealed and there is no evidence of leaks, but I am curious does this need to be relubed with new oil? What is the best method to do this? Does the whole axle come off or is there a short cut that a professional might use to do this? Any advise/help is greatly appreciated.  

Answer
 Hello Jerry:

 First thing to do is Replace the Old Belt. If this doesnt help, please let me know. Also the Control linkage may be out of adjustment a little. Hope this Helps. The Hydrostatic drive Transaxles are not repairable by most mechanics. They have to be sent back to the manufacturer.  Hope this Helps.

 Good Luck

 Respectfully

 John