what's goin on? I own a 2000 blazer, each time I hit 40 MPH my truck jerks/jumps like when your driving a MANUAL S-10 and each time you shift gears it does that jerk thing. now whenever I come to a stop sign or a red light, as i slow down almost to a dead stop my truck feels like down shifts or like a jump/jerk itself forward and theres a quick noise coming from the driveshaft area? but from me preventing it doing that, I shift in Nuetral before im at a dead stop and it wont jerk forward. When I put it back in Drive after a minute goes by, it wont jump, but if its less than a minute (guessing) as I put it back in Drive it'll do the jump/jerk thing a couple times. And this only happens once each time I start my truck. My step dad told me it could be my U-Joints? I do have to replace my U-Joints because I hear a little clunk but is that whats causing it? (bearings inside?). Last witer of 2010, when I put it in 4X4 low, it felt like it did the jerk right away as I accelerated, or is thats what suppose to happen? need help on this one please. Thanks