front end still shaking

Just checking to see if anybody has advice on the front of 2002 4X4 shaking violently when hitting a bump, it has 50,000 miles on it all I have changed all ball joints- stabalizer shock-- ride shocks -- and changed tires, still can't get it to quit ! I had a friend stand beside the road and watch when I hit a bump and he tells me that the wheels are not bouncing but shaking severly,( long ways from town or he said he would have walked home), I have heard others with this problem but they all solved theirs by selling the truck ,

Do a search on this forum for "Death Wobble" and you'll find a couple of answers in that thread.