Pinion angle - have a vibration

Cal-Tracs normally call for very little down pinion angle and using SS springs, which can provide a lot of rise, call for as much as 6*. As mentioned, shocks also have an influence on rise/seperation.

Here is an old thread on the subject.
http://www.forabodiesonly.com/mopar/showthread.php?t=160127

FWIW, a while back I had a vibration and it turned out to be a spread yoke. You could actually manually feel the driveshaft move up & down in the saddle, just a tiny bit, even though it was all installed correctly. But it was enough to spit the driveshaft out on the next run. Went to billet yokes ever since.