Hi everyone. Im new and look forward to exchanging information. So I changed the rear diff oil on my 2012 Frontier pro4X and the oil was like chocolate milk. I assume this is water but I dont do any off roading or driving in water. Any idea what has caused this. The reason I drained it is because it started making a humming noise at around 60-80km/hour and stops when I take my foot off the gas. There was only a few tiny metal flakes on the drain plug magnet.