I've had DW with stock suspension, and lifted suspensions, and cured it.
As to geometry, not Exactly, this is true of the FORD front suspension with a SINGLE trailing arm, Dodge has 4 links. On a ford the axle rotates so that lowering the axle (lifting) rotates the axle forward, decreasing caster and necesitating dropped trailing arm brackets equal to the drop of the axle(lift).
On our dodges, the axle is trailed by four links. on each side there is a link above and a link below the axle, these trail back to frame mounting points that are about the same distance apart as they attach to the axle. The effect is that as the axle moves down the lower arm 'pushes' the bottom of the axle tube forward, and the top arm 'pulls' the top of the tube rearward by the same amount, the caster angle does not change.
Now the true geometry is improvised a bit as the spacing isn't the same at both ends of the links, the lengths of the top and bottom arms are offset to account for this and there is a bit of bias so that the caster angle will increase on compression which aids in return to center feel when you are driving over curbs and such.
The actual loss of caster even at 4" of lift is only about 0. 5 degrees, no where near enough to cause DW. (An old Ford F150 swung +/- 5 degrees!).
DW is caused by worn ball joints, tie rod ends, track bar, steering gear, soft or uneven sidewall pressures or stiffness ( want DW, put on BFG 315's and stagger the tire pressure 10 pounds).
Lifting keeps the caster roughly the same, pulls the axle rearward (looks wierd in the wheelwell without extending the trailing arms, really high lifts run out of bar angle/range and need dropped brackets, but not at a resonable 4" lift) and shifts the axle to the side (also strange if you don't change or drop the track bar, but the axle moves side to side during action anyway so the adjustment is only for looks at ride height), and dropping the track bar requires dropping the pitman arm to maintain absolute parallel alignment of the steering and track bars to prevent 'bump' steer.
However, factory alignment sucks and so do most alignment shops. The Caster Cams allow the axle to be twisted all out of proportion causing excessive cross camber caster angles even when overall caster is correct, and tramlining or uneasy feel on a crowned road. If you can't drive your stock truck comfortably with one finger, repair whats wrong, re-align it, then lift it. Don't lift or add 'performance' components to cure the problem or you'll be chasing your tail and cussing your vendor because it will amplify the problem.
DM
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