Michel
This is far too complex a problem to try and explain here. I had the same problem (not a D&D) scary to drive at speed.
It took me 2 winters of massaging to correct mine and it now is the best steering vehicle in my fleet of cars ---01GMC p/u--09venza--13sonata.
Part of the solution involved a custom width rack from flaming river.
2 sites i recomend you visit and print out their articles on bumpsteer, if you follow their advice you will be able to correct your problem.
1--Longacre---Tech section
2--heidts---
Craig