I stumbled across this place on E-Bay. I saw a new front back motor and snapped it up. It showed that my gears were stripped too. A little googling turned up a Mustang monthly article showing the replacement of the tracks from this place. Their tracks are larger and have a lifetime warranty to boot. Once I ordered them I realized it was the same place I got my motor from on E-bay. Since my up down motor is weak I'll be ordering one of them as well for a fresh track mechanism at a fraction of the cost of buying one. For any track parts from 87 to 98 this is the only place I've found to order them.
http://2men1garage.com/
http://2men1garage.com/