Check the stuffer timing.  I've had a few Hesstons,  Had to quit them because of the shields.  Went back to Jd 348s.   Liked the inline, but after AGCO put MF on the balers they acted jinxed..  Could not keep 3 in the field together , 1 or 2  would be down for some minor problem.     I also HATE driving on hay, so I had tires set wide enough not to, would have to remove wind gaurds so the tires would not hit them. Now with the new shields over the flywheel I could not deal with them.  Lotta fun without the shields replacing shear bolts with a  HOT slip clutch, can't think the extra shield helps.