Looks like I'm the only 4.0L timing chain issue on here. Got my truck back Tuesday, $1810 lighter. I went ahead and had the water pump, plugs, idler pulley, and belt/s changed while they were there. I also had the original oil leak fixed, including rear timing chain plate seal, valve cover (cracked), and valve cover gaskets. Turned out to be leaking from behind the timing chain back plate.
If your warranty is about up, have the timing chain tensioner checked.