Bad vibration??

Mine started the same vibration your describing about a week ago and crawled under there and looked at it a couple days ago. On mine the carrier bearing is good but the rubber around it is slightly rotted and is causing the drive shaft to vibrate at higher speeds. Hope this helps.

I replaced mine thinking that might help...didn't <img src="{SMILIES_PATH}/icon_mad.gif" alt=":x" title="Mad" /><!-- s:x -->

Air ride tech used to have a very detailed and precise way to set up your angles, but I can't find it on their site anymore.

Anyways start at 3 deg and see what that does.