Here's the story. Last October the truck,'51 GMC, was running just great then my crankshaft broke. HAd the engine out had all the work done and re-installed everything. Know I am getting a vibration at about 40mph. Tires are good king pins are new etc..

Here is my thought and give me your thoughts.
I kind of remember when I put the drive line back together that the ball
housing on the rear U-joint went together pretty tight. I mean I really
had to torque the bolts down on the "ring" that holds the ball into the
"socket". I did this because I used Permatex to make the seal. But I am
wondering if I way overdid it. Is this part suppose to have some flex to
it?
Also I did a Search and one comment that came up was "u-joints being "out of phase". Since I have a longbed does this mean both u-joint have to be lined up?