What was your last mod before you noticed the vibration? Is your driveshaft angles maxed out? Any chance that the extra weight is enough to reduce the angle just enough to resolve the issue? I'm just thinking out loud...
Do you notice a shift to the passenger side when you have a passenger? I don't know how soft your springs are...
This all started when I put duals in. Putting the driveshaft into phase didn't change anything. Next up to try is to drop the crossmember to the lower position so that my cases are not contacting the body.
Body Mounts Tight?
I'll have to check this.
