While replacing O2 sensor (postcat) i found some wet oil from the area between transmission oil pan and transfer case. The oil leak seems a while ago and i don't see any oil drops in the area but it's wet. I checked transmission oil pan gasket all the way round and oil is not coming from there. I changed transfercase and rear/front differential fluid at 75K miles, all i remember when i pumped transfercase fluid it spilled out some and i cleaned right after the bolt locked.
Look at the photos below, do yo know where is the oil coming from?
