Cascadia Cummins ISX 400 10 speed Shakes when accelerating. At any speed, even while parked.

Sounds like a injector is not firing any fuel into cil.

 

Beat me to it lol.

 

Find a new, competent mechanic to use. King pins and alignment should have never factored into this problem. Two excellent guesses above just listening to a 30 second video.

 

The ISX is a straight 6 cylinder engine. There are a couple of advantages of using a straight 6 engine. One of them is that they are inherently balanced in terms of their firing order. You can deactivate one or the other fuel banks to determine what bank the cylinder mis-fire is on. You should be able to do single cylinder deactivation as well.

From the video, it is clearly a misfire. Just like mentioned above--most likely an injector not firing at all....or no compression on that cylinder.

My specialty is detroit, and I was able to do this on a DD15 rather easy to determine the offending cylinder. Cummins, I'd imagine they should have something similar.

 

Here is a video showing the process I described above.