Hello, My first post here but I read and learned alot from this website, I have a problem with my 2007 trailblazer LT 4wd (high miles). It drives smooth no noise or any other issues except that on medium to high speed the steering wheel shakes for 2 seconds on sharp bumps(no loud noise) I checked the front end on both side and I noticed one bad upper ball joints and a wheel bearing and I replaced those already by myself but the shaking is still there. I noticed the front tires are worn unevenly and the shocks are rusty. Is it possible that the tires are causing this? shocks? I can't see that tie rod is bad is it possible that I missed it? When I ask a mechanic they want to replace everything, well of course replacing everything might solve the problem.It's true the other ball joints have the rubbers broken but they don't shake when I tested it. any suggestion please. Thank you!