Shaking under front end
 

Let me start off by saying that I have been a reader of the Blazer Forums for going on a year, awesome site. I finally decided to join instead of being a lurker and just reading everything off and on.

2002 Chevy Blazer 4x4 with 106,000 K
My question is.... I just replaced my ball joints (Moog, upper and lower) due to having the crappy stock ones popping while driving. I also took it to aChevy dealership and had the front end alignmentdone. Now when I turn the wheel and go to back out it vibrates and shakes under the drivers side front. It feels like having a mudder rub the a arm or wheel well.
I know 100% that my tires are NOT rubbing. It mainly does it when I go in reverse with the wheel turned and sometimes when taking off slowly. It only does this for a few seconds and then it stops.

Any ideas?

Thanks guys.
Jimmy