Call the John Deere house in your area...they will know this...most John Deere Dealers only work on John Deere., and in my area, we don't have those..Texas...but, any John Deere House will be able to tell you...I can work on the engines...anything el...
John Deere is not the company they used to be. I doubt they have a tensioner and if there is it has little, little adjustment. If the belt keeps breaking clean you better bring it in for some warranty work. If it shreds everytime your working it too ...
There were in fact some John Deere tractors that were painted red but they were generally only for special industrial orders in the 1960's.