my truck shakes when going 70mph
 

Hi, I have a 1989 chevy c3500 dually. I just replaced the tie rods, upper and lower control arm bushings, and ball joints. It drives way better now, but when I got on the freeway it was shaking side to side. I could feel it on the gas pedal whatever was shaking. Any ideas?

I would suspect that you are feeling too much positive toe, although it sounds like you have probably affected all three angles, and caster can affect high speed handling as well. You might get by with simply having the toe checked and adjusted, which could eliminate the shimmy, but your camber is most likely off too, and although I don't think that it would cause this particular problem, it will affect tire wear, so I would opt for a complete alignment at this point.

Ya I was going to go get an alignment, I just wanted to make sure I dont need to replace anything else before I do

you prolly due:

Sway bar bushings
Sway bar end links or, at least, bushings
Idler arm, if you have one, which is likely you do
possibly Pitman;

Why don't you do a thorough steering components inspection? Those trucks do not tolerate any slack and play.

I did the idlers ARM and pitman ARM as well. I just found out that the regards didn't balance my tires because I bought new ones. Ons get em balanced and get an alignment and see what happens...

Also, you may want to check the steering shaft. GM trucks have a rubber rag joint. They can tear over time.

Yea its torn. So is every one I found in the pick ur part. How would that affect the suspension?

It won't affect the suspension. But, it can allow the steering to become loose, even vibrate at higher speeds. This can feel like suspension issues.

If it's torn, it should be replaced. Just ask for a "rag joint" at the parts store.