I know a few guys that get 17-18ish w/ the manual tranny runnin empty, but I don't know about loaded. maybe 13 dunno. Check the ball joints see if the seem wore out, ussaully they are, Also ask them if they have any service records. I wouldn't be afraid of any 7.3 w/ 120k that had good service. I sold one w/ 200k that is still runnin like a champ.