Trans Fluid Change

[Shooter]

I'm doing my first yearly service and plan on changing my Trans fluid tomorrow. I did a search, but have more questions than when I started. I read that I will not be able to suck all the fluid out with an extractor. Someone mention running it in gear to mix the junk off the bottom before extracting. I also remember another thread that said you should never run the boat in gear out of the water because it’s bad for the packing. Doing this on the water is out of the question.

Do I need to run the engine temp up before changing the Trans fluid or can I do it cold?

[h2ohangtime]

If you have a dripless packing gland and you hook it up to the hose, the packing gland should be fine. It's the cutlass bearing on the strut that you might damage. I don't really see a safe way to get water on it while it's spinning unless you get a second hose and a spray nozzle that can reach it from a distance. Even then, I don't know if that's going to be enough water since it wouldn't be submerged.

[WakeSlayer]

Just extract the fluid that you can, and replace. Warm or cold. You will be fine.

[DanielC]

Go get your boat warm, by using it. When you get the boat home, change the fluid them.

NEVER run your boat without supplying water to the raw water impeller!

The issue with running your boat when it is not floating is the raw water impeller. It needs a constant supply of water to lubricate and cool the impeller, because of its tight fit inside the pump housing. Running the boat for even a very short time can slightly damage the impeller, causing it to fail completely sometime later, when you are nowhere near your trailer.

Back to the transmission oil. You should change the fluid every other oil change, and at the end of the season. I have done this on my boat, (1997 Ski Nautique, 2290 hours) and the oil still comes out of the transmission looking and smelling new. If your transmission fluid is clean like this, the residual amount left in the transmission will not be a problem.
I use my boat for a lot of Show Skiing stuff, and towing docks, and jumps, so my boat has not had the ideal life of just pulling a Slalom skier for about a 17 second run.

On boats I have had to flush out the transmission completely, (not mine) after sucking out the transmission, about 2 quarts on the 1.23 to 1 transmission, I disconnect the oil line on the top of the transmission, and gently blow in to the line, through the oil cooler. This moves the oil in the cooler in to the transmission sump, where it can be sucked out. If you do this you will need to get three quarts of oil, but you will only use a little bit of the third quart to fill the transmission.

The way I check the transmission oil is this. In the drive way, I level the boat. Then I push the oil dipstick in only the first O ring, or bump. I look for the oil level somewhere between the two lines. I then launch the boat. With the boat floating, and running, I shift into reverse, neutral, forwards, and back to neutral.
I then check the oil level, with the engine running, pushing the dipstick all the way in. Again, somewhere between the two lines. It can be a near the top line if the transmission is hot, closer to the bottom line if the transmission is cool, but always between the two lines.

[Shooter]

Thanks guys, great information! I would always hook a hose to my boat so running the impeller dry is not an issue. I live over an hour from the lake so I don’t think doing the service after use will do much good for me and I don’t think the lake would like me changing fluids in the lot. One of your comments got me thinking, I could suspend the junk somewhat by blowing air into the extractor hose before pumping it out. This sounds a bit anal, but I’m just worried that the bad stuff settles on the bottom and would build over time.

[WakeSlayer]

Your drivetrain will still be plenty warm after a one hour drive home.

[DanielC]

The biggest reason for doing the fluid change hot is that the fluid has a much lower viscosity, and is easier to pump.

I can understand the desire to be "anal" about the transmission fluid. Again, on my boat, the fluid comes out looking, and smelling almost new.
One way to get a good idea on how dirty the fluid is is to do this test.
Get a white paper towel, and put a drop or two of your transmission fluid on it, and let it sit. Do the same thing with new transmission fluid. Compare the looks of the two spots.

[mlkissel]

Couple things I have learned over the years about tranies, and the one that I have heard over and over again is, never replace all the fluid at once. Over the years the fluid coates the parts with a thin film of lacquer. Changing all the fluid at once can strip this lacquer and clog up pours in the tranie. Most manuals recommend changing only the fluid in the pan every year which is about half of capacity. If you pump out what you can and do that yearly, this will keep you fluid fresh and not be a shock to your system. I have also read many times a lot of transmissions fail within a year of doing a flush which was recommended by a mechanic. Don't mean to alarm anyone, but just change what you can pump and enjoy the boat.

[DanielC]

There is no advantage in purposely leaving dirty transmission fluid in the transmission. If there is so much gunk inside the transmission, that putting new fluid dislodges it, and it causes problems, you are way overdue to do a transmission fluid change.
PCM recommends changing the transmission fluid every 100 hours, and at the end of the season. That is what I have done with my 1997 Ski Nautique, with over 2290 hours, using the boat a lot for show skiing. Without any transmission problems.

My suggestion is to check the fluid, and see how dirty is is, using the paper towel test I described above. If it is dirty, after the change, do it again.

[Shooter]

My trans should hold 2 Qts and I pulled just over 1 Qrt. It didnt look that dirty. It was a easy job with the pump. Thanks for the help!

[AirTool]

I agree with mlkissel in principal and he really should be referring to the same abused transmission DanielC is referring to. I've seen several "neglected" auto transmissions ruined by a fluid change. I've nursed several that never had a change at over 100k so I sucked out two or three quarts and topped off. Did it again in six months then again, lather rinse repeat. Several are gone to new owners and two I have still going strong.

Transmissions that have been cared for will not suffer from this issue.

Agree the fluid should be changed hot and one hour of cooling is still plenty warm.

Here is a guideline on tranny fluid. Dex 2 was designed to last 100,000 miles at op temp of 160F. Every 20 above 160 cuts the life of the fluid in half. (New cars run much hotter than in the 70's, so change often.) The tranny of the average Nautique owner's boat runs so cool the fluid might decompose of old age before broken down from use. Having said all that, I've changed my fluid every summer or every 50/60 hours (I'd have to look at my log) because it is a good thing to do, very easy, and cost is about 6 to 8 bucks. When I compare my sucked out fluid to my new fluid, I wonder again why I'm doing it. The answer is because it is cheap and easy, it gets me out of the house and in the boat, I'd regret otherwise, and I love my Nautique.

Note I suck out 2.25 quarts HOT and put back 2.0 cold. On the next trip, the level has been perfect every time.

[Onside135]

Anyone have any recommendations where to get a good pump for pulling fluid out of a PCM transmission?

[DanielC]

I have used a manual hand pump, and it worka fine. I also used a pump that draws a vacuum on a large empty container, and that work too.
I found an old medical vacuum pump in the basement, my deceased father used to suck gunk out of this throat, and I have repurposed that to suck transnission fluid.

[jtryon]

Anyone have any recommendations where to get a good pump for pulling fluid out of a PCM transmission?

this is the one i got, gets very good reviews. http://www.boatersland.com/moe035330...FS8V7AodswcA9Q

[vision]

Make sure to check PCM's recommendation for your transmission based on year. PCM recommends NOT changing transmission fluid on newer transmissions. It is because of the reasons stated above.