I've replaced the steering gear box, power steering pump, rotated and had front end allignment checked. All the tie rods, idler arm &pitman arm are all tight and in good shape. But it still wanders and needs constant correction on uneven roads. Smooth high ways or even roads not so noticeable. Any suggestions on what might still be the problem. Allignment center said the wider tires will cause some wandering but it shouldn't be this bad I don't think. I've had other trucks with bigger tires and haven't had this problem.

All suggestions would be welcome.

While driving, is the steering responsive? In other words, is there any movement in the steering wheel that doesn't result in a change in vehicle direction? (is there any noticeable play in the steering wheel when correcting?) Keep in mind that just because the steering gear box is new, doesn't necessarily mean it was adjusted correctly at the factory, or rebuilder.

Provided there is not excessive play in the gear box or rag joint, and all suspension and steering linkage parts are good, (upper and lower control arm bushings, upper and lower ball joints, inner and outer tie rod ends, center link, idler arm, sway bar mounts, end links and shock absorbers), and tire pressure is at the maximum stated on the tire, I would have the alignment shop increase caster toward the maximum side of the tolerance, (if spec is 1 to 3 degrees positive, set it at 3 degrees). Set camber and toe at the desired spec, (in the center of the tolerance). If your alignment shop will work with you on this, you'll find a problem with one, (or more) of these things. Hope this helps.

What is the best way to check that the streering gear box was adjusted right other than constant trial and err. I want to do this myself instead of taking it in as Christmas is here and money is tight.

Is there noticeable play in the steering, (see post #2)?

If not, have them increase the caster to the maximum allowable, (see post#2).

Finally back to the wandering truck problem. In post #2 you stated to increase caster to the max. of 3 degrees and said that you will find a problem with one or more of these things. My question is increasing the caster may correct my problem or this will help point out where the problem is? If this just points out where the problem is will I need to have the caster set back to the minimum of 1 degree?

I'm not sure of the exact caster specification for your vehicle, the alignment shop will be able to tell you that. In their specification book, or computer alignment machine, it will give a minimum and a maximum caster specification. The alignment shop should inspect suspension and steering linkage parts before aligning the wheels. When they align it, have them use the maximum allowable specification. Caster affects steering effort, how quickly the steering wheel returns to straight ahead after cornering, and the ability of the vehicle to track straight down the road with the least amount of wandering. The lower the caster, the more tendency to wander. Caster is not a tire wear factor, camber and toe are. Adjusting caster to it's maximum allowable will give the most stability, and least wander.