Here are some thoughts from an engineering perspective that may help some of you guys get to the bottom of your DW problems. Resonant Frequency Every mechanical system has a resonant frequency. This is the frequency at which the system will go into oscillation, which is a condition of uncontrolled or increasing vibration. This is what is happening with the DW, your front suspension is being excited by a bump, etc., at its resonant frequency, which causes it to go into oscillation. The heavier something is, the lower the resonant frequency. Automotive designers spend all of their time trying to raise the resonant frequency of their subsystems. A higher resonant frequency is not as likely to be induced by the forces placed on the vehicle from external sources such as road imperfections. Unsprung Weight If you have spent any time paying attention to modern automotive engineering publications, you have heard the term "unsprung weight". This is the weight of the suspension components that are below the springs. One of the major pushes in modern suspension design is to reduce unsprung weight. This increases the resonant frequency of the unsprung components, and decreases the likelyhood of oscillation. It also means that smaller, lighter components (shock absorbers) can be used to control the oscillation. This is the main reason why everyone has gone to IFS - it reduces the unsprung weight, therefore reducing the weight of the entire system (along with improved steering geometry). Spring geometry The stock front springs, with their negative camber are about as good as it gets with a leaf spring suspension to keep the axle firmly located side to side. Since the axle is pretty much in line with the shackles, there is very little leverage on the spring bushings when the axle is forced to the side, such as when you are turning a sharp corner. As your lift springs get taller, there is increasingly more leverage on the spring bushings, shackles, and the frame. This allows for a lot more side to side motion of the axle assembly with a given amount of input force. Now for the DW. You have added a great deal of unsprung weight to your front suspension between the Dana 60 (+200 to 300lb?), and the big tires (100 - 200lb?). This weight lowers the resonant frequency of the system, making it more susceptible to oscillation induced by external factors. Most also have lift springs, which add leverage to the side to side motion problem. The front shock absorbers do a good job of damping the up and down motion of the front axle. They do basically nothing for side to side motion. So what does damp the side to side motion? The only side to side connection is through the steering system. Even a steering stabilizer only acts between the axle housing and the tie rod - the connection to the chassis is still through the steering box. Why do so many different things seem to make a difference? Anything that affects the resonant frequency of the entire system could change or eliminate the DW. If you change the steering stabilizer, maybe the DW will go away, maybe it will happen on a different stretch of road. Why would changing the PS pump make a difference? The power steering system is a closed loop system that attempts to keep the angle of the output shaft of the steering box in synch with the input shaft. When you induce a large external load onto the output shaft, the PS system (steering box and pump) will attempt to counteract this and keep the output in synch with the input. Because of this, the particular pressure that your pump is developing will effect the resonant frequency of the system. Higher pump pressures will increase the resonant frequency of the system - lower pressures (read - worn out pump) will decrease the resonant frequency. Under these large external loads, the PS system is doing some steering that you are not involved with. Once the oscillation begins, the loads that are being transmitted through the steering box are likely orders of magnitude larger than what the engineers at Saginaw Division ever expected this stuff to encounter. Stiffness Stiffness is a good thing (ask the ladies). Any part of your front suspension or steering system that lacks stiffness is going to lower your resonant frequency. The little short drag link that GM used on these trucks is really stiff. Does anyone use a crossover drag link that is not straight? That is not as stiff as a straight one. Is your tie rod bent? A bent tie rod is not as stiff as a straight one. Do you use soft spring bushings to increase flex? They are not as stiff as hard ones. But why do some almost stock trucks have the DW? I would suspect that the PS pump or box is bad, the spring bushings are worn out, bad tie rod ends, or a combination of any of this stuff. DW is a huge problem with D/C vehicles that have coil spring front suspensions. Some of them do it at a very low mileage - replacing the steering box or pump has been known to cure it. I would guess that if you could compare side to side, you would see that the trucks with Dana 60s and big tires resonate at a much lower frequency than the trucks with stock stuff. OK, what can I do to stop it? I would like to see someone try running a steering stabilizer from the frame to the axle housing. You would want to mount it as close to horizontal as possible. Maybe make a bracket that mounts to several of the diff cover bolts so that you can attach the stabilizer to the top of the diff housing, and then as straight as possible to the frame from there. This should not really limit your suspension flex if it is horizontally mounted. Somebody try this and let me know.