i got a 97 k3500 dually i have a bad vibration starts at 50 gets worse at 55 gets better at 60. it makes a loud humming noise to. i have checked and the ball joints and tie rods are good. the drive shaft has no signs of damage all the weights are still on it. have balanced the tires and replaced both front unit bearings and still no change. any one have a similar problem and know what could be wrong with my truck. the only thing left i can think of is the tires which were put on before i bought the truck and are still reasonably new only have about 4000 miles on them they have no visual defects but they are cheap tires.

does the vibration come from the front or rear? You can usually tell if its from the front because you feel it in the steering wheel.

i thinks its coming from the front cause i start to feel it in the steering wheel before it vibrates anywhere else the steering wheel will vibrate at lower speeds.

try rotating the front tires to the rear and see if that fixes it.......

good luck

i thinks its coming from the front cause i start to feel it in the steering wheel before it vibrates anywhere else the steering wheel will vibrate at lower speeds.

Check the front wheels, there is a ring that goes between the lugnuts and wheel.If not installed right you'll have a balance problem!!!!