So it all slowly started with humming sound fronn the front and slowly progressed. All intermittent and switching to 4WD would mostly stop it for a while.
Later it got louder and sometimes would happen in 4WD as well.
I went to a friends workshop and he tested the vacuum/ lines and also changed solenoid.. Checked IWE and discovered the teeth were bad shape apparently due to me driving.
He vacuum tested lines and changed the IWE gear set.. All ran well few days and then again same humming sound.
Funny thing is it sometime also can be felt in 4WD.
I rechecked vacuum using a vacuum pump on each wheel, tested enagement and disengagement, tested leaks in the line and even drove around with vacuum gauge attached and it maintained 25 hg pressure. ,

Not sure where to go from here. I would see a dealer but want to ask if I could do any more diagnostics before spending more $$.

Thanks

 

Were the splines on the axles damaged (since IWEs were damaged)?

 

They apperaed to be ok. Initial thought was that it could be the bad bearing.

 

I'll try to help, but first, does it sound like this? Just trying to narrow down what you are hearing. At this stage, I "think" you may be looking at a bearing.
Tell us if this is what you hear.

 

sounds siilar but intermittent. just FYI, the bearing was replaced as precaution. Since I have tested the vacuum lines only when truck is stationary and a short stretch on road, I am thinking maybe certain motion of steering or bumps in road or acceleration may be causing the line to leak in some place and then again disappear . Should I just change the vacuum lines as well ?

 

Maybe pull a vacuum downstream of the solenoid, see if it holds. If so, turn your wheels one way or the other, both sides, and wiggle the rubber lines, and see what the vacuum does.
Whenever someone changes out an IWE, I usually ask, who, and how the spindle nut was tightened and torqued down. It's imperative the IWEs are properly engaged, or a vacuum pulled at each IWE.

 

I didnt wiggle the lines while vacuum pump was holding the pressure. Is there any video that shows the process to torquing the nut ? I can ask the shop if the followed it. They are generally very thorough

 

I don't have a video specifically for it, but this video does describe how to do it. This guy knows what he's doing, and has many videos that are dead on. Just be patient and watch the whole video.

 

^^^^^^Don't worry about the years covered, your 2016 is identical.

 

Thank you
Looks like something I can do my own as well if needed. I do have all the torque wrench and workshop goodies.