[honeykeeper]

Well I read this entire thread......not in one sitting of course!
I have an 05 Titan with Off-Road and Big Tow and lots of mods. Mine is smooth at all speeds and I took it to 111-13 MPH once to see the high speed limiter kick in.
My Titan has 72K on it and I plan to "keep" it.
Good luck to ALL in persuit of a "NORMAL" ride and dealing with NISSAN.

Death Wobble

If you're asking what "Death Wobble" or DW is all about it's when a vehicle starts to oscillate to the point of feeling like it going to come apart and only goes away by slowing the vehicle below the speed in which the oscillation begins.
DW isn't caused by any one factor.
DW's are caused by a rather simple problem, but one that can be hard to track down. Your suspension system (which includes the body) is out of equilibrium. Energy is being temporarily stored somewhere and then released, and the cycle repeated. Energy storage can be in many different areas. It can be in the sidewalls of the tires flexing, or the rubber in the bushings of the springs and control arms, or in the springs, or even in the flex of the body. The energy being stored is caused by something being loose in the system, such as ball joints,
tie rods, control arm bushings, leaf spring bushings, motor mounts, etc. or something out of alignment.
What makes things tricky is that you can have all of these problems and have no DW. It has to do with the rate at which the energy is stored and released. If the storage and release rates are close to the same, you are in for trouble. That is why changing tires many times will kill DW. The new tires are stiffer or softer than the old
ones and as such store and release the energy at a different rate.
The purpose of a steering damper is to change the rate of storage and release of the energy, just as are your shocks.
You can have all of the equipment working correctly and still have DW, but in most cases there is a defective component that you haven't found yet.
1- Check all the rubber parts first. They fail the quickest and store/release the most energy.

2- Look for loose connections/connectors such as tie rod ends and loose or worn ball joints.
If the ball joint is worn or loose, it can allow lateral wobble. Worn ball joints are a danger anyway as they may fail and cause uncontrollable steering loss, but by allowing the wheel to move laterally and independently of the opposite wheel they can also contribute to DW.

3- Steering Stabilizer. A tight steering stabilizer can mask problems with the steering, but if it's loose it may allow DW to occur in cases where it normally wouldn't have.

4- Poor Alignment. The first question when someone has handling problems after a lift is whether they had the vehicle aligned. More than half the time, it wasn't. Don't proceed until that's taken care of.
The front tires will be toed-in following most lifts. When you hit a bump on only one side of the front axle the tire will begin to bob up and down. Since the Control Arms are no longer horizontal, they will pull that side of the axle farther back as it goes down - this will turn the wheels slightly to that side. Once the tires pull to that side, the 'scuff' of the vehicle traveling straight ahead will slow the tire and begin the same process once again.
If the stock control arms are used, the pinion will start pointing down, away from the t-case output shaft. As it points down, it changes the caster of the axle and therefore throws off the self-centering engineered into the axle. Remedy this by using adjustable control arms.
Drop Brackets can also help reduce this, since they bring the control arms back to a more horizontal position. Sometimes this can be caused by excessive toe-in of the front wheels-think of it as the tires being cross-eyed and not knowing which tire is dominant
Check toe in (difference in the distances between the front edge of the front of the tires and the rear edge of the tires.

5- Unbalanced tires. Once again, as they start throwing the axle around, the only way to stop it is going to be by slowing down.

6- Unbalanced driveshaft or driveshaft U-joints out of phase by 90°