I would put the recommended shims back in the way your manual tells you too with the correct thickness for each part of the clutch (neutral, high, low). The shims are available from AGCO at a reasonable price, or at least my local AGCO dealer had some on the shelf that weren't very expensive. Most of the time, it's a matter of moving shims from one spot into the next to adjust engagement or the neutral, but in your case it looks like you are maybe missing some thicknesses in there. Maybe somebody adjusted wrong sometime back in it's history? I set the PD clutch up on my D19 right to the manual tolerances and it has not given me a problem, even shifting it under a heavy load, such as plowing. I hope this helps you out.