I've driven this thing around quite a bit lately. To work and back a few times, around town a bunch.... Driving it has been great except the grabby new clutch.
Then yesterday was my first time driving it with the 37"s. It drove fine about 10 blocks. Then I pulled it into 4hi, hubs unlocked. Just to see if the front end/TC made noises. About a block after that I got death wobble.

.
I can't think of how the axles being engaged with the hubs unlocked could affect anything...?
And it has brand new king pin bushings and springs, installed before it was put in the truck. Gotta be tires. Balanced with ceramic beads. Could them be getting out of whack some how? Bumpy roads were involved. I know people balance their big tires that at alot, and I used the recommended amount per tire size.