Soft rubber in the DS support bearing. I fixed mine by getting a one piece DS fabbed. The trans support is pretty soft also. Women love the vibes coming through the seat cushions2007 Prerunner Double cab with 1.5 inch blocks. I have not yet put in the carrier bearing drop, but the people at wheelers told me that it may not cure the problem.
I think that if you read all of the posts regarding this vibe issue, you will find that most peeps still have a small amount of vibe on the 05-07 trucks with the shims and carrier bearing drop. I just put the dakars on mine and gained another 2.0 inches of lift and got back some of my vibes. I have a small vibe when I take off, but no harmonics at other speeds. This was a freeking science project for me to fix the last go around. Now I have to play with it some more.:saw: :welder:I have a 1.5 inch angled fabtech steel block in the rear with OEM leafs. I believe the angle of the block is 1.5 to 2.0 degrees. It vibrated though with my deavers as well. My old truck which was an 06' DC taco prerunner as well had deavers and they were actually smoother the the OEM springs, WTF?