They didn't say but I assumed it was the diameter which allowed a loose fit in the bearing. Yes it was the rear axle shafts. To eliminate other possible sources they removed the rear driveshaft and drove the truck with the front wheels only.
Gary

 

Having chased down vibration issues on lifted and modified jeeps for year, you need to get the truck on jack stands at each corner (under the axles so the truck is rigidly planted) and "first" run the truck in 4 wheel drive and do a visual to see if the wheel and/or tires are wobbling in any obvious way. Just put the truck in drive and get out and watch how the tires rotate. No need to run it up to 100 mph, 20 mph is plenty fast enough. This includes looking for tires that are out of round, which is not uncommon. If the tires are more than 1/8" out of round, you will certainly feel it on the road.


Getting a little more technical, you will then need to run down to Harbor Freight and pick up a $20 dial indicator and magnetic stand. Mount this combo to heavy piece of plate steel that is sitting on top of a 5 gallon bucket and start measuring the run out of your wheels and drive shafts, both front and rear. Max run out, both horizontal and axial, I'd accept is .010".


I've found wheels that were bent, tires that were not really round and drive shafts that were well beyond the .010 measurement. All can and do contribute to mysterious vibrations.


Last up is pulling drive shafts and running around in front wheel drive and just rear wheel drive to see if that affects anything. With a full float rear end, as already mentioned, it could be an axle shaft and you could pull those too to rule them out. The Ram crowd is having a vibration issue with their axle shafts on some trucks.


If you swap out wheels and tires, make sure the truck they came off drove nice and smooth so you know the wheels and tires are good. Also, only change one variable at a time so you can better pinpoint the problem.


Good luck.


Adam

 

Removing the rear drive shaft would not rule out the axle shafts if they happened to be bent for whatever reason.


Adam

 

They removed the drive shaft to try and isolate which component was causing the vibration. As a result of that test they pulled the axles and found the problem.
Gary

 

So, I had to add 560 pounds on my 350 KR 8 foot bed king cab, because my significant other noticed a bounce, however keep in mind I my KR came with 3rd suspension spring rear and front heavy duty suspension package.

I used the puzzle weights, excellent outcome,

 

You can't put the truck in the air and run at any speed due to stability and traction control. You have to locate fuse/fuses to disable it. Tried to do this, Nightmare. I aired my tires to 45psi, rode sloppy with no change in vibration.