I have a 2005 Sonata 2.4l and I have been having some engine vibrations for a while after a timing belt replacement. It took a few tries to get the timing right but I still have the vibration. I recently had to replace a pulley on the tensioner assembly because it was making a noticible noise. When I was trying to get the timing marks aligned by using the rotating the balance shaft looking for the spot where it comes back to the the mark method I could not find it like I did in the past. Rotating the balance shaft gear was not smooth. Is it possible that shaft is warped from so much time vibrating?