When you got the tsb done, did they go from a 3 leaf to 4.... 4 to 4.... 4 to 3.... Or what?
Also I torqued my U-bolts to 75 ft/lbs because I thought 37 ft/lbs can't be enough. The vibration got MUCH worse. Also the whole truck shook when braking which it did not do before. So I went back to 37 ft/lbs and vibration is barely noticeable. I come to figure that the 37 ft/lbs is a toyota band aid for the vibration.