Propeller shaft spins while in 2WD

Just found out that my front propeller shaft spins in 2WD and creates a shudder/vibration, goes away when in 4WD. It also goes away when I put a zip tie around the crossbeam and the front shaft to keep it from spinning in 2WD. So the sound is drive shaft related (front). Check out the video I made.

https://youtu.be/5ad64Y2jlTI

 

Not nessisarily, this was discussed at length back in the original vibration thread, and many tied off the shaft and still had vibration, some reported improvement but the general consensus is that the drive shaft was not the cause of the vibration most were feeling in the V6 trucks, and that is is more engine exhaust harmonic vibration.

 

No this is directly tied to my vibration/shudder issue, when I tie off the front drive shaft my vibration completely goes away.

 

Pretty sure that shaft should be pretty balanced, didn't seem so at all to me

 

it has weights towards the back like it is

 

Yes but that doesn't mean it's actually balanced. It should be but I've seen driveshafts be out of balance with weights on them. Just like tires

 

great, you found your problem

 

At my 15K service (I asked them to do the transmission update), but they also retorqued the propeller shaft and lubed the driveshaft, and now my truck runs smooth as silk. I never had a really bad vibration, but the before and after was completely noticable

 

hmm i might tr

I might try and to re torque the bolts and see if that yields any results, I have already greased it. I have a read a few things regarding viscous coupling from the transfer case that, when cold it will create enough fluid friction to spin the front drive shaft causing this vibration/ shudder, i dont know if that is true tho. also i am thinking it could be a bad bearing somewhere on the yokes, either on the ADD or at the transfer case, idk tho.

 

yeah, but the vibration/ shudder has to come from some type of bearing that is rotating with some type of friction. I think the spinning drive shaft exerts a force onto the bearing creating it to shudder/vibrate. why it does it I have no idea.

 

I agree with you, i am saying that maybe the weight of the shaft is affecting either the yoke pinon bearing from the ADD or the yoke bearing that comes out from the transfer case. idk which one if any. All i know is that the vibration/shudder goes away when i zip tie the front drive shaft to the frame and when i switch it into 4WD. It also is less noticeable when it gets warm.

 

yes i explained my concern to them and they said it was " normal characteristics" i call BS, there's no way a new truck should make that sound.