Front end hum in 4wd
I have an 01 Grand Cherokee 4.0 I6 with selec-trac and about 145k. The frontend makes a noticeable hum when accelerating in 4wd Full Time. When the gas is let off the noise subsides. In 2wd the noise is not present at all. From doing some research I have been wondering if the pinion bearing in the front differential is bad? That's just a guess, the noise isnt absurdly loud YET, because I assume it will the more I use 4wd this winter season. Any input would be great!