Recently only in 4x4 my front end has been making noise and the front drive shaft started chirping, all hands pointed to a u-joint issue but after checking them we came up with nothing. I checked the fluid level in my front diff and it was all milky. Next step is to pull the cover off and drain the fluid, the magnet on the plug had no metal shavings on it nor was there any in the fluid on my finger after checking. I am new to this so if anyone can point me in the direction of what to check for when I have it open to see if there's a big problem going on it would be appreciated. Thanks!