I have a 99 2500 with a 6.0 I picked up about a month back for a price I just couldn't pass up. Recently I put a new pitman and idler arm in, new inner tie rod ends, did a front end alignment, and new u-joints. Now at about 45mph the truck has a vibration. You feel it mostly in the seat and in the gas pedal. I'm out of ideas. Could it be a wheel bearing or possibly as simple as an out of balance tire? I know it's been a few thousand miles since the tires have been balanced. Thanks for any info guys.

No ideas huh fellas?

No ideas huh fellas?


Sounds like a driveshaft issue. Comes in around 45 then smooths out some if you go faster? Even if you mark everything and put it back together all in the same order you can disrupt the original balance with a U-joint change.

(Assuming you've revved the engine up to the same RPM as 45 MPH in neutral and the vibration doesn't reoccur and your engine and transmission mounts are sound.) To isolate between drive shaft and wheels put the rear axle on large stands and remove the rear wheels. Use two opposing lug nuts on each rear brake rotor to hold them tight to the hub. With the front wheels chocked start the truck put it into gear and accelerate the drive train up to 45. If it vibrates with the drive train at speed and the wheels out of the equation then it's the drive shaft. You have to match mark the yokes and shafts and reassemble it back in the same positions to maintain factory set balance. Also make sure all U-joints are centered and none are binding.

Vernon

no the vibration get's worse as you accelerate.

The vibration was there before changing u-joints. Still can't figure out what it is.