Timing cover and injection pump gear
 

I just picked up a first gen Cummins, of course the first thing to do is the KDP. As i took the timing cover off and at the very top by the injection pump gear it looks like it has rubbed a little bit. I took a wrench to see if I could tighten the nut on the gear, it moved about a little less than a 1/4 turn. Could the gear be warped or is there another cause?
https://cimg9.ibsrv.net/gimg/www.die...a584de39a9.jpg

Did you check for endplay? The whole shaft could be walking in and out.

Has the injection pump been changed? Could have been the old pump doing it?