Loud Humming Noise

I have a 1998 Blazer. I just bought and it only has 86000 miles on it. While I'm driving, there is a humming noise and the faster I go the louder it gets and when I'm on the freeway its even worse. Now when I'm on the freeway and I hit a dip in the road that kind of jumps the car, the noise goes a way for a quick second and then returns as soon as I'm on flat land again. I've asked a bunch of people, some say I need to get new tires, but the tread is fine. Some say that I need to adjust my torsion bar to level out the ride. I have no idea what it could be. HELP......SOS.........

What Motor Does It Have And Is It A 4x4?

I have a 1998 Blazer. I just bought and it only has 86000 miles on it. While I'm driving, there is a humming noise and the faster I go the louder it gets and when I'm on the freeway its even worse. Now when I'm on the freeway and I hit a dip in the road that kind of jumps the car, the noise goes a way for a quick second and then returns as soon as I'm on flat land again. I've asked a bunch of people, some say I need to get new tires, but the tread is fine. Some say that I need to adjust my torsion bar to level out the ride. I have no idea what it could be. HELP......SOS.........

The normal problem is a front bearing assembly but other possiblities are cupped tires, or possibly differential noises. Did you buy the car from dealer and does it have any warranty?? If it has 4wd , does it go away when it is in 4wd??

I bought it off private seller. I did try to put it in 4wd hi and it worked for a second but then it came back. Everytime i hit a bump as it bounces the sound goes away and comes back. I was thinking that it could be the bearing but I only have 86000 miles on it but I'm willing to try anything. Thanks for replying.