New user here, 1996 f150 4wd. I've been getting 'death wobble' if I go over 40 and hit any bumps. Tie rods were just replaced and bushings are good and I can't find out what it is, can someone please point me in the right direction. Thanks

 

Check the linkages that connect to the steering box. Those wear and the play can cause wobble.

 

It's called the rag joint.

I would get a front end inspection done. I would bet there is a ball joint issue. The OEM components on these trucks being non greasable are lucky to survive past 100k miles. I had to replace everything well before 100k miles had accrued.

 

^ This.
You obviously have severe wear in one or more components that have not been replaced. Shocks and ball joints are a natural place to start. A good "front end shop" can evaluate for you.

 

Check the front axle u joints out by the wheels
If one is binding up it will cause the death wobble (shimmy)
Easy to check
Jack up the front end and turn the wheels to near lock
Engage a 4x4 hub and turn the wheel
If the tire flops back and forth the u joint is binding and is the cause of the bad shimmy
Good luck
The front tire(s) are not full of fix a flat right?