Ok , I decided to change the rear and front diff oil today. My truck is a 05 with about 440 miles on the odometer. I took drain the rear diff and it was dirty!!! , I couldnt believe what i saw , the oil was a dark greyish color. Anyone with a 05 Titan should really think about changing that rear diff oil. The front diff was clear and could have gone alot longer before changing.

Great. I was hoping this might be unnecessary on an '05 but apparently not. Nissan should be microfinishing those rearend gears too I guess. :) What oil did you use?

I went with mobile 1 , for front and rear , gonna do the transfer case today, I will post up the results when im done.

The way it was explained to me is that before a rear diff. is broken in the tolerances are so tight which causes more friction which causes more heat enough to shear just about any oil they put in there down that added to the metal floating around in there its a good idea to change it after it is broken in regardless. I heard second hand from a guy at work that took his 350 deisel in for this thinking somethig was wrong and this is what the ford tech told him he said if you change the fluid early you can almost double the life expectancy of it. Well anyway at least we are not the only ones with black gear oil in our rear diffs

I'll buy that theory. When I used to wrench on musclecars I had a 8 3/4 rearend in my Dart and it had an easily swappable center section and no rear cover. The finish on the 3:23 original gears was like a mirror. I had a new 3:91 center section set up for drag racing and the finish on that new gearset was nowhere near that nice - it was almost rough in comparison. A LOT of metal has to wear off to get to that mirror finish.