Yeah check the rack damper or rack dampener or damper pin. It's basically a bolt with a spring in it that "damps" the pump's vibrations.
Is the idle rough or is it 'smooth' but lopes? As in, is the idle speed consistent or does it go up and down?
Mine used to shake and the idle speed was constant. So, I lowered the idle to a point where the shaking isn't as bad. It still shakes though but... it's part of the diesel thing
good luck,