I have a Craftsman zero turn mower, model 107.277700. The idler pulley on the main drive belt disintegrated...I need to replace the belt and the pulley...dropped the mower, can see most everything....can't figure out how to get the belt around the left side tranny pulley...there's no clearnace at the top between the pulley and the frame to slide the belt through...this one has me stymied...what do I need to do to replace that belt? I've looked at the schematic, no help...I can physically see it...just don't know how to create clearance for belt to slip over pulley.