Small Engines (Lawn Mowers, etc.): Belt Problem or Worse?, driven unit, hydrostatic drive

Question
I am looking at a well kept John Deere SX95 rear engine riding mower. I have never owned a rider so I am not familiar with the workings of these. Heres the deal. This is a belt driven unit with 7 forward speeds and 1 reverse. The engine runs great but when shifting from 1st to 2nd or 3rd there doesnt seem to be much difference in speed. The owner says he has never changed any belts for 6 years. I do know from testing other machines that the higher gears will provide more speed. So could this be the drive belt or something more involved? I am wiling o spend 150.00 or so more to get this machine working properly as it is in great shape and worth more than the asking price. I hope that I have given you enough info to help me. Thank you very much. Tony.  

Answer
 Hello Anthony:

 The Best way to Check the Drive Belt is to find a Grade (hill) and Put the Mower in a High Gear, ie. 5th, or 6th gear. If climbing the Grade in 5th or 6th Gear the Belt Slips and Smokes or Squeals, then Replace the Belt. If no Grade is Avaliable then Chain the Rear Frame of the Mower to a Sturdy Tree and using the Lower Gears, pull on the Chain. Do the Wheels Spin or Does the Belt Squeal or Smoke and Slip. If the Wheels Spin the Belt is Fine. If Slipping, Replace the Belt. Is this a Hydrostatic Drive Transaxle? My Manual shows Both Hydrostatic and Mechanical Transaxles come on this Model Mower. If it is a Hydrostatic Drive, then the Ground Speed Difference Will Not Change that much in the Lower Gears. Hope this Helps. Let me know what Happens, Please.

 Good Luck

 Respectfully

 John