Carrier Bearing/ Rear Vibration Issues???

The other day I posted some questions about alignment and got some fantastic feedback. So today I came up with some new questions and concerns. I read some forums and saw some videos on rear vibration issues (2006) but it really didn't answer my questions, is this a problem or can you leave it? will it have any long term problems/effects? Does a carrier bearing drop really work? how about 2.5 - 3 degree shims, do they really help? Any recommendations would be great or if someone has tried shims or carrier bearing drop kits. Truck currently has 3" lift.

 

Degree shims exist for a reason - and that's to fix driveline vibrations from lifts. The kicker is - you gotta have the proper degree shim for your situation. Too little degree won't fix the problem yet too large of a degree can go in the opposite direction and cause more vibrations.

My 96 tacoma had re-arched leafs with an additional leaf. When they were done with the install - the rear was 3.5" high. I had some obvious vibes at all speeds. I installed a 2.5 degree axle shim and it all went away - and never came back after the suspension settled to be about 2.5".

I'd go with axle shims first.
Only use the carrier bearing as a last resort if you need to.