Screw all that grease bullshit. I had the same problem. It got worse and worse. It is your A-ARMS!! Tighten ALL of your A-ARMS! You might have to have it done unless you have a bigass breaker bar or something. I work at the chevy dealer and had one of my suspension buddys do it for me. It got so bad that when i would brake you could see the right front wheel shift frontward and then backward. It was worse on the right front. I would be standing still at a light then turn the stearing wheel and the damn thing sounded like it broke off but it was just shifting when the wheel was turned. Hope this helps.