My cousin runs a JD dealership and has told me before that JD puts out a kit to slow down the shaker shoe on the Titan 2's. I have heard of a couple of Titan 2's shucking the shaker shoe like yours has. WW
The bushings that your shoe rides on are worn out. When you do replace them, and you are torquing the bolts that hold them in place, make sure the shoe is in the center of it's travel so thet the rubber mounted bushinds have equal "twist" each way. Also, as has been suggested, replace the sprocket that drives the shoe with the one used on the older machine.