The 6.0 Powerstroke unison ring can wear out and need replacement. In this previous post I explained the 6.0 powerstroke VGT problems and shared how to fix them. If the problem is ignored, the unison ring can wear out as well as the vgt arm. Here is a replacement unison ring:

If you plan on rebuilding the 6.0 turbo charger, here is our upgraded 6.0 powerstroke turbo rebuild kit. If your turbo is not repairable, you can buy a 6.0 powerstroke turbo here.