Adding a lift kit and big tires on your truck can wreak havoc on certain drivetrain components. The one under consideration today is the loss of driveshaft engagement from the axle being in greater droop from it's original position. The easiest solution for me was fabricate a metal spacer that pushed the two co-linear driveshaft pieces back together.
A small ring of material was left on one side in order to keep the spacer concentric and well balanced, and a similar ring removed from the other side. It fit very nicely.