757 ZTrak™ AC Gas Engine W/60 Inch Mower Deck
2005 Model (Serial No. TC0757B040001-050000)
You can find the years for almost all models by going to JDParts.com, enter the model number and search. Select your model from the search results and then at the bottom of the 1st page there will be a "Product Information" section. IN that section is a PDF document. If you open the document it will list the serial number breakdowns.