I did a search, and found a couple of things, but no closure. I have 2" blocks in the rear of my truck, and when i am towing a trailer(very light load...maybe 3000 lbs) i have a vibration from 60-67 MPH. The vibration is there crusing at the speed or excelerating through. I assume its my driveline angles. I've replaced my u-joints and carrier bearing about 15,000 miles ago. It all looks fine under the truck. My question is, do i need to drop my carrier or shim my axle? How do i know what to do and how much? Thanks.

Joe

also sounds like it could be tire related...etc..out of round or not balanced right maybe