Originally Posted by pepepeter
I drained, flushed, and filled both the transfer case and rear differential with the Valvoline 80W-90 durablend synthetic gear oil. It went smooth, but getting off the filler and drain plugs was a challenge. In both case the old gears were nasty looking and filledwith black shavings that seemed more like a sludge than metallic particles. See pics.
Is the rear diff fluid on the left and transfer on the right? I remember rear diff fluid worse than transfer at 22,000 miles, but not so much as yours. If so, rear diff works very hard and stresses the fluid a lot. This is a remainder for anyone who never did one of those to do it before its too late.
The problem with gear oils is like ATF, if you wait too long and gears adjust to thick goop, changing to new fresh fluids, especially low viscosity synthetics, causes new noises and sometimes failures. I had that in my Subaru and learned a lesson.
BTW, how much metal did you see on the magnetic drain plugs? That is graded in 3-tier system: fuzz, whiskers or Christmas tree.