Originally Posted by Powaaah

Had similar issue about 5yrs ago, and it turned out to be a combination of tire cupping and differential carrier bearing. It took the dealer a while to solve it, with chassis ears and stethoscope. It was driving me nuts so I know the feeling.
When you add a level kit, did you also happen to do the UCA?

Originally Posted by wrgb

kinda.

I did both IWE, then did the tsb to engage them all the time. Guessing that the iwe were broken and that’s why the tsb didn’t worth the first time.

I had to use zap strap to test vacuum originally.
eventually got some much stretchier thicker tubing (exercise tubing actually) that worked great for the different size nipples for testing vacuum.

This combo got rid of 90% of the vibrations.

still can feel it a tiny bit but might just be how it feel with iwe engaged.


happy because the next thing to look at would have been front diff or transfer case or something bigger.

Originally Posted by knightwheels

Interesting, thanks for the info.

I did a lift and new/bigger tires but it was present before any of that. I need new UCAs so I think I'm gonna throw in new IWEs while I'm at it. Will look into the TSB fix as well.