driveshaft issues

[muleys67]

Hello, all. My 86 longbed has a vibration at hiway speeds so Im replacing ujoints and carrier bearing.Upon separating the 2 halves of the driveshaft I found a small plastic piece under the nut that separates them was broken into several pieces.This keeps the shafts together supposedly.Where in the world will I find this plastic ring? Its under the thin metal nut on the long shaft.I dont think I can run my truck without it.Suggestions? Thanks, guys I appreciate your help.