brickbox wrote: ↑Thu Aug 22, 2019 6:26 am
In addition, when I'm going highway speeds (about 78MPH), the vibration is worse when I am in 4WD Hi vs. 2WD.
Running highway speeds in 4wd Hi is a definite NO NO. Don't do that.
You can run at those speeds with the truck in AWD auto mode, but not in 4wd hi.
I'm not surprised the vibration is worse when doing that.
The first thing is to look for the obvious: tires out of balance, and then driveshafts/u-joints.
I had a seized u-joint a few years ago that caused that problem.