ok, i have 2000 Silverado with an odd issue. 1. it is not repeatable, it happens when it wants to and is not very often, but every time scares the hell out of me. 2. first time it happened, i hit a moderate bump in the left hand freeway turn, at about 65 mph. all at a sudden, the whole front virtually went up in the air and into uncontrollable up and down and side to side shake. was pretty major. it felt like front wheels bounced off that bump and resonated. total chaos. 3. it repeated itself on the same bump maybe twice more, so i learned either not to go fast over it, or keep wheels straight 4. same resonating shake occured on several more occasions on different roads, every time fater hitting a bump in the road. 5. today, it did the same two times in a row, on a straight stretch of freeway, after slight bounce. every time this happens, it's pretty bad, car shakes and bounces vigorously, steering wheel goes left-right, front bounces up and down. truck has 76K miles on it; i bought it with 58K on; first time it happend about 4 mths ago. otherwise, it drives smoothly, just kind of is "snaking" left and right at hwy speeds, but usually that's when you have those groves in the hwy from long use. i do not like it. every time this happens, it feels like car will flip over. every time steering wheel is in slight turn. slamming on the brakes fixes it, but i am afraid someone will rearend me for this. i have 2 theories: shocks and stabilizer bar. nothing's hanging lose, no leaks under the car. shocks feel fair for truck. somehow i have that feeling that it's just made this way, and i hit it in a "sensitive" way and it goes into that resonating shake. also, lord save my wife drive it and this happen. any ideas?