I've got changed the oil in transfer case and both differentials. Filled up with synthetic.
I noticed that oil is leaking (not much, but notisable) from the plug on rear differential. The oil filler plug has plastic shim, which I do not understand purpose of, because it doesn't seal the plug anyway. So the leak is from behind of this shim from fill plug. Drain plug is ok, the oil level is ok too. Did I have to apply some kind of sealing compound on plug tread or it 's because synthetic oil?
