I sure hope someone here can help me. I have been dealing with this problem for a couple of years now but its just getting annoying. I have a 2004 2wd avalanche 1500. My problem is when the truck sits /parks at one spot for a long time a day or 2, the steering will be loose when it is first driven. When I mean loose I mean the steering wheel will shake violently back and forth on a straight a away. After about 10 minutes of driving, the shaking will go away and will not come back unless the truck sits over night again. I have changed out the pitman arm, Idler arm and the dealership promises me that after changing out the steering mid shaft that it will go away (a year ago), and it has not. The wheels are balanced and aligned. No unusual wear on the tires. The next thing im looking at is the unit that the idler arm bolts to. It connects the idler arm to the frame but i do not know what it is call. Do you think that could be the problem. Thanks in advance. I did a search on the site but it seems that everyone is referring to the steering mid shaft.