Transmission fluid

Was thinking about changing the oil in my 1997 nautique with gt-40. I have never done this before. Dextron II is what the manual recommends. Is Dextron a brand name or a type of transmission fluid? Can this be bought at the auto part store? Any difference between transmission fluid for a boat then a car? Could someone please give me a recommendation? I have tried using the search feature but so many different topics on transmission. Oh, can this be done with the boat on the trailor. I was just going to pump out what I could and add back new the same amount I extracted. Also I have noticed a difference in colors of the fluids for sale. Is it ok for them to mix? Lots of questions sorry.

In or out of the water doesn't make a difference. Suck as much out as you can. You can't get all of it out. Fill it, run it and do another oil change. The different colors don't make a difference. Just stay away from the synthetics.

Dextron is a type of trans oil. Yes, one you found at Advanced is good as long as it's not the sythetic as mentioned.

Fly100 wrote:    I tried to suction my fluid out at the weekend, but found a drain on the bottom and did it that way.Suction only got about a pint out.

Your lucky you were able to get to the drain plug. Typically you can't without tilting the aft end of the engine up and the reason most as well as Eric suggestion sucking. Yes, you can only get about half of the oil out.

You say run it and change it again, does the transmission have to be in gear? I guess I am asking does the transmission fluid circulate with it not in gear?

Yes, to some extent the fluid does circulate but there may be some old still left in the clutch circuits. Lube the cutlass with some soapy water and "blip" the trans forward and reverse a few times.