This is more than likely an alignment problem do to the lift kit.
The drive shaft has to have the correct angles or the shaft will set up and start a harmonic vibration.
To correct this most will rotate the axel housing. In rotating the axel housing it kills the caster, AKA king pin inclination.
Most will try to control this with a steering stabilizer unit.
The only way I know of is to cut the ends off of the axel housing, set the pinion angle for the drive shaft, then reattached (welding) the ends (steering knuckles’) to give the correct caster.
Wish you the best its a lot of work but will pay back with a truck that is drivable and safe.