8-3/4 help

Hey gang.. Have no idea if I will explain this correctly but here goes.. my buddy just got the chunk all redone for his 63 Fury.. 8 3/4 with 410 gears.. sure grip... apparently when they were tightening everything up.. theres this 'pin' type thingy in the sure grip that holds the spider gears together (or in place.. however you look at it).. well.. it broke.. We called Randy's Ring and Pinion.. they dont sell that part.. I am wondering if anyone has sure grip parts laying around.. it has to be for the sure grip unit for a 742 case (the one with the buttons) if anyone has any clue what im rambling about or may have the part or knowledge of where to find the parts, please let me know... thanks