This is for a 2007 FJ Cruiser, but with 1GRFE it could be any Toyota so equipped. I'll start by saying this was a major bonehead move and since I was not present I have only the details I can gather from my conversation with my son. He had an issue with loud chain noise and when he removed the valve covers he saw that the passenger side tensioner may need replaced, but the main culprit was likely the main tensioner was froze up. He did not move to tdc nor lock the valvetrain before attempting his repair and in his words "the camshaft timing gear ratcheted", I am assuming that the tension on the passenger timing gear caused the chain to slip since he had the main tensioner out so now timing is hosed and with zero clearance timing this thing likely needs to be torn down and returned to spec. It has not been started. I am looking for the best way to dig into this. I am ok with removing the timing chain cover to return everything to factory, we did the timing chain replacement a couple of years ago on my v6 tacoma so I am familiar with that part of the process, but am looking for some assistance on how to proceed with this since I cannot achieve TDC without fear of valve to piston contact. Should I be removing the camshafts to relieve valve tension and then proceed? Many thanks in advance!