I drained oil today from rear trans axel of an 85 446 that I just picked up and the oil was tan in color, never saw this before. I did find when I bought the tractor that the long bolt in the right rear seat support was missing and the previous owner only used this machine to plow snow for the last 7 years (It has 522 hours on it). I think that maybe it got some water in the rear? Could that have caused the tan colored oil?? Anyway I put in one quart of an 80W-90 gear oil for the rear and there have been dif opinions about filling the rear with more than one quart of oil? The rear drain plug has an additional plug just above it and the manual says that is where the oil should be filled to, once it starts comming out of that plug then there is enough oil in the rear?? Does it really matter if there is more than that? I filled the rear from the top right bolt hole at the rear seat supprot.