Still haven't resolved the vibration issue.
Below is a pic of the way it was at first. #1
And then the way it is now with three heavy washers under the back of the axle perches. #3
In all positions, I haven't really noticed a significant change in the type, intensity, or duration of the vibration.
And it still occurs right around 37mph or 1900 rpm.
My thinking is it has to be the driveline itself.
If it was the pinion angle, I'd expect the vibration to change in some manner. But in all three positions in the pic below, the vibration remains the same.
