Yesterday I installed a Yukon Duragrip in my '04 Yukon with the 8.6" 10 bolt. I used approximately 2.5Qt of 80/90wt gear oil and what I guessed to be 2oz (about half of a 4oz bottle.) I was surprised that the diff was quiet the first drive while turning in a circle at full lock both directions. I wonder if i could have used half as much FM?