[amac209]

sounds like you bent something. i would get this into the shop as soon as possible could be a lot of different things you might've twisted the frame rail or knocked the rear diff out of allignment and it's "dog tracking" or maybe something in the steering linkage is bent. about all you can check in the driveway is the toe, measure the distance between the tires at the front of the tires and the rear. also check the balljoints, tierods, idler& pitman arms. you might've started to shear the pitman shaft, at any rate get this truck checked out.