2007 Dakota, 3.7 V8, Auto.
A couple of weeks ago, as I was pulling away from the house, I decided to shift into 4WD because of snow. Truck was running, I think it was already in gear, and I just reached down without looking and flicked the selector switch one click to the right. As I started driving I was distracted by a few things and drove a quarter mile before I noticed the 4 LOW light flashing, and realized that the truck had already been in 4 HI when I turned the switch one more click to the right. I pulled over and put the transmission in neutral and let it shift into low, and then I switched around to various positions to allow it to move correctly through all positions, and then put it in 4 HI and drove on.

Now, whenever I'm driving at city speeds in 4 HI, around 25-30 mph, there is a resonating gear howl. It's not very loud but I can hear it and feel it. Have I damaged something?

 

It won't shift into low unless you have it in neutral, I don't think that would have damaged anything. Check the fluid level in the transfer case.

 

Have you tried putting it back into 2WD/AWD?

 

What does the tag on your transfer case say after nv or np?

Btw putting the switch into 4 low does nothing till the shift conditions are met. (Neutral and under a certain speed)