Yeah I've looked at that and from what I have read and researched, I "think" that my pinion angle is a little too high. I have the double cardan shaft and when you look at the pinion angle, it's pretty much lined up straight on with the shaft. Supposedly this is the ideal setup, but when I get to highway speeds and accelerate hard I get a vibe. I "think" this is due to the pinion climb. So when the weather gets nicer I'll mess around with taking the shims out and see what happens. Overall it's a big improvement just to get rid of the shudder, even with the new found high speed vibe.