XHD Leaf Springs

I spent a fair amount of time this morning looking at various internet sites, and happened across several of those mentioned by OldVart. I now know what the pinion is, how to measure the angle between it and the driveshaft, and where to order shims. So I obviously need to take some angular measurements on the Cuda, and decide which shims to buy.

Curiously, though, none of the articles on "pinion angle" say anything about the ungodly harmonic noise that I'm hearing...... they do, however, mention vibration. I'm not doubting your very helpful advice, but I didn't drive it fast (or far) enough to notice if I was experienceing any vibration.