driveline shake at highway speed

My 2006 Tacoma has a vibration at highway speeds.not related to throttle position. I just had all 3 u joints replaced, rear tires balanced etc. Vibration still there. The vibration also can be felt when starting from a stop or coming to a stop. Any thoughts?

 

Man, my first thought was ujoints (I had mine replaced a month ago: problem solved) but you already did that.

Why only rear wheels balanced?

 

No. I haven't checked the carrier bearing. Would that explain the shudders? I know the carrier bearing on these trucks is a weak spot.but could that fail with only 70k on it? Also,where should I order a new one from? Im thinking I should order one,and take it to a shop and have them replace it and balance the shaft. I just don't wanna throw parts at it though.