I have a John Deere 160 lawn tractor. I let my brother use it and while he was mowing a belt broke. It's not the belt that turns the blades on the mower but a belt that runs from the back of the deck to the front of the mower. I don't know what that belt is called (I know it's not the drive belt because the mower still moves when I put it in gear. Can someone tell me the name of the belt and tell me what size belt I will need to fix the issue. Also, any tricks or instructions for replacing that belt would also be helpful. Thank you.