I took the 4Runner for a drive tonight. It was the first trip out with Mobil 1 synthetic in the rear differential and dual transfer cases plus 3 quarts of Redline MT90 in the transmission topped off with conventional. The purpose of the drive was to slosh the oils around and to see if I fixed the minor leak by replacing the rubber boot on the front transfer case shifter. What I noticed was the entire truck feeling more loose/free and the sound is also different. It seems a difference has been made though that wasn't really the goal.