You've got alot of threads touching on basically the same subject.... So I'll just blahblahblah at this starting point: Let's rewind to an older thread of yours: http://www.rangerforum.net/f38/sick-these-fricken-camber-problems-please-help-me-out-2771/. And check out post #32. This and other threads show this truck has issues that need addressed. Many. Shaking of the steering wheel at speed or the entire truck wiggling back and forth can mean a few different things. Something as simple as out of balance tires. Out of round tires too (egg shaped). Or egg shaped or bent wheels even. Or bent rear axle wheel flanges. Could also mean bad outer OR inner tie rod ends. Could be bad BJ's. Or as someone told you, tires internally falling apart (cord separation from carcass). The later usually doesn't happen unless the tires are upwards of 15-20 years old or more. Shocks don't really cause what's happening. Tbar preload doesn't cause that. Bad U-joints don't either...those'll squeek and vibrate, not shake. Judging by the linked thread above and what this thread has said, I think it's just full on front end slop. Don't find yourself a normal run-of-the-mill mechanic who fixes everything under the sun that has 4 wheels....find a specialized Frame and Alignment shop. These places tend to really know their shiz and discovered things I missed on mine during my recent alignment. They actually found a ball joint nut that wasn't tightened all the way... could be one of your issues too maybe? These places are alot of times where 4wheeldrive shops take their customer's cars for alignment after lift. Definitely is worth the money to really have the entire suspension and steering checked out. I just have a hard time believing a 140k+ truck has original sealed everything(save for passenger TRE). I know the issue has disappeared, but it seems odd for it to shake on ya then all of a sudden problems disappear.