Mine was doing the same thing, it was like riding in a washing machine that was off balance. Thing is, it was intermittent, sometimes it would do it two or three times a week and sometimes I'd go months without the "death shake".
I was banging my head on the wall, jacked up the front end, nothing seemed loose. It did not make any sense.
I'm happy to report that the truck has not had the death shake since January and all I did was balance and rotate the tires.
Hell if I know.

 

i had the same problem all my front end was tight, i was frustrated well i got some 89 ford wheels and bfg tires for really cheap and i havent had the wobble since. haha for all u ford guys this dont mean the truck runs any better.

 

i took my truck in for axle joints and they also found ball joints and bad wheel bearing which prob tore up removing it. i can see where guys think there truck is tight since mine is 08 dodge with 31k on it. i never had death wobble either. truck drove good