I really want to keep the lift because I actually do take it offroad here in Utah a lot. I really wanted to know if the steering dampener was put there by the manufacture to cure a design problem I guess.
I think mgOstisha and Danger are on to something though. I found on the net that even trains can experience this, called hunting. There wheels are coned shape so that when the train tries to veer right on the tracks, the diameter where the right wheel contacts the tracks increases and the left wheel decreases, cause the train to try and go back left. At certain speeds this can get out of control.
Here is what I came up with a while back...
I know that the wheels shake violently side to side, and it can start from a small bump and get worse in just a second. One reason it interests me is because I work on vehicle for a living and have seen it a number of times.
I've been trying to find info on the internet, but can only find what people say to check and do to fix the problem, but not the science behind it.
The following is my theory. I maybe partly wrong or totally wrong. First I want to explain a few things.
Camber is this tilt of the tire at the top either in towards the vehicle(negative), out(positive), or 0 deg.(straight up down). Caster is the forward or rearward tilt of the steering axis(imaginary line drawn through the upper and lower ball joints).
Caster is used for directional stability. Caster will normally be positive, upper ball joint behind the lower ball joint. If you turn the R.F. tire right it will be trying to lift the R.F. of the vehicle so it will try to turn back to the left. The L.F. tire will be doing the same. That is what gives directional stability and helps the steering wheel return to center after a turn. (This will also cause a pull if caster is higher on one side than the other. It will pull to the lower side.) You can demonstrate this w/ a coat hanger. Imagine the corners of the coat hanger are the ball joints and the hook part is the spindle. If you tilt it back and then pivot the coat hanger at the ball joints, turning one way, the the spindle will move down therefore trying to lift the vehicle. You can actually see this if you look closely at vehicle w/ a lot of caster that is stationary and turns the wheels all the way in one direction. Trucks, Jeeps, SUVs, etc have higher caster normally than cars. Another thing that happens because of caster is that camber changes when you turn. This is how caster is actually measured when alignments are done. The person doing the alignment turns the wheels a certain amount each way and the computer measures the camber change. It then calculates caster.
So what I think happens with death wobble is that first of you hit a small bump, and the tire turns right just a little. Then camber also increases in the R.F. tire, and decreases on the L.F. meaning both tires are leaning right. So now it is causing both tires to pull right and store more energy. Then the effect of the caster causes the tires to return to center and go past center to the left and the cycle continues. The only way to stop this cycle is to dampen the energy. One way is through the steering suspension. There is friction in the ball joints and steering linkage. Also the gear box, but not very effective because of the indirect connection(unlike rack and pinion), and even less effective in lifted vehicles because of the greater angle. Another is the steering dampener. It is just a shock. It takes the kinetic energy and changes it to heat energy. Also lowering caster. But lowering it too much will cause wonder. By the way Ford also has the same problem on their solid axle trucks and recommends lowering caster but still keeping it within spec and changing the steering dampener. I ran into this recently on a Jeep with only 12K miles. I still checked the suspension and everything was good. The only thing he had done was different wheels and tires and a 2" spacer lift. He decided to take it where the lift and tires were done though and have them look at it.
