ditchpickle1

I have the exact same problem and just found the issue. On mine, right under the front of the seat, there are 2 white clips that are attached to a tube. Either they are lose or need to have a lubricant around the tube so they slide. Im guessing they are lose because the passenger side seat is solid. The white clips are tight on passenger side. When I put my hand on the clips and push the seat side to side, they clunk when the seat moves. Hopefully this helps. Looks like I found the problem on my truck. I have an appointment Thursday to have the rear window shroud resealed and Ill have them look at it then. Hopefully can tighten them down. Check your rear window for leaks also. Mine and my neighbors are leaking. I didn't know about it until my neighbor told me and I saw mine leaked too.