So I bought a filter kit and set about to "service" the transmission. The problem is I don't know the service history. When I checked the level before I thought, hey it looks "pink" - sort of diluted - as it ran down the side of the pan. Then when I started to drain it today, it looks brown. Appears red on the edges where the light can get through. It doesn't smell burnt or really any worse than new ATF. At 113k miles should I just try to pump the quart or so I drained out back in (although from a new quart) and call it good or do the whole thing? I was thinking about drain and fill, drive for 1,000 miles, and then drain, fill, plus filter. I just don't want to put new fluid in it and learn I need a rebuild, which seems to be the risk.