Adjusted the valves today and all but 1 needed adjusting.
Helped a little, but the vibration is still there..

I did put in an new rack damper about 1 month before the
problem appeared. The rack damper is all the way in, and not much
happens if I back it out 2 or so turns..

The problem actually gets better with a hot engine.

Inspection of the trans mount shows that this was not likely
changed.. This will be my next guess..

Timing chain stretch is about 4 degrees, so this seems OK

Zero smoke... 27 to 28 mpg on the highway.

Reverse definately quiets down the noise/vibration.

To recap what I have done. New Motor mounts, eng shocks,
shock bushings, filters, pure luber molly diesel purge.

How to tweak the idle??

I am almost stumped.. Lets see what the trans mount does...

Thanks again for all the tips..

Dan