For over a year I've had this noise in my 2015 Dodge Journey 3.6 AWD. It seemed to begin* when I installed new tires last Fall. The new tires I installed, I did so in pairs as I couldn't afford all 4 at the same time. The difference in the treads however was enough to cause some noticable noise in what I concluded was the transfer case.
When I got the other tires on, a couple weeks later, the noise subsided mostly. But over time has crept up in amplitude and is now loud again.
I've tried to research how to get into the front 'diff' but it seems to be part of the transaxle / transmission. Which makes me sad.
The transmission fluid was changed out about 2 months ago, and aside from it being the original fluid and showing it's age, it wasn't burnt of indicative of heavy wear inside the transmission. I am unsure where or how the gearbox that powers the front axles and the drive shaft gets it's lubricant from, that that is what I am hoping to check.
I've replaced the front axle shafts. The Right side one I replaced 2 years ago as that was making a similar noise on the Right, and that did solve the issue at the time. I replaced the Left one this past weekend, and the noise did decrease slightly, but there is still a noise there. Even tho the wheel bearings seem solid, I purchased new bearings, and plan on doing those in the coming weeks. *Note: I mentioned it seemed to begin last Fall. But like I said here, the sound was similar to the front axle sound I experienced 2 years ago, which upon replacing that CV Axle shaft on the right side, it fixed it.
The noise is consistent with the speed of the vehicle, and doesn't change if the vehicle is shifted into neutral while rolling. Turning and breaking don't seem to have an effect on the noise either. The noise isn't noticable until you are going about 25mph+.
Should I fear the worst, and start saving for a new transmission? Or what? :P