LJ 5si jamming and paper is under tray3

I have a 5si with a duplexor. It has about 400k on it. About 100-150k pages ago I got a new fuser,duplexor,PU rollers above the trays. Then the fusor gear broke and we got another fusor about 60-70k pages ago. Tray 3 has always jammed so we dont use it. Tray 2 just started jamming. I will have an accordian wrinkled paper in the fusor and I will have multiple pages under tray 3. This is happening very frequent now. I started using the feeder tray 1 and it seems to work so far.. What worn parts could cause these issues?