It looks like Matt at Independent4x has a complete set of busings. I'll start with bushings since they are easy. I'll do shims next if that doesn't help or help all the way.

Now, when it comes to shims, I want to make sure I have this right in my mind: The added torque makes the pinion crawl up higher on the ring gear. This is turn makes the front of the pinion shaft go down. That increases the angle and that increase is what is making the vibration. That means the thicker part of the wedge goes forward, or towards the front, if I get shims.

Sound like I got this??

NCDiesel

NCDiesel