Egr don't knock. egr on the 6.6 gas is built in to drivers side valve cover up front and runs to intake right above TB ,there is alot of vacuum on it and pulls alot of contaminants from engine block, be worth your while yo put a catch can on and a good one trust me all are not the same , RXP is a good one good luck
Has anyone been told by GM or anyone with motor knowledge, what this might be ,get it out there and lets see what it is these are great motors and we need to get to the bottom of it
Yep got a 6.6 gas 2500 2021 tik knock at idle around bell housing area, goes away in drive and reverse. But with no load on it its there, i hope someone can find out the problem