Contaminated Transmission Fluid

[49waves]

I'm getting ready to do some cruising on my newly-purchased catamaran but was just informed that my port transmission fluid is contaminated with water. Problem is I can't haul out where I am (Ensenada) because the boat's beam is too big for the travel lift.

What I'm wondering is how serious a problem this is. I am planning on hitting La Paz in 2-3 months, where I can haul out and hopefully drain and clean the transmission fluid / replace seals / etc. Is this asking for trouble?

Engines: 3GM30
Sail drives: SD20

Thanks in advance.

[perchance]

Water in the drive will destroy it in short order. This not something to ignore in the hope that it will go away.

[Captain Bill]

Right now you may still have some protection from the oil, but what ever you do don't run the unit at max RPM as the water in the oil will boil and completely destroy all the seals. When that happens the unit will blow out all the oil and then fill with sea water which will completely destroy it. You can pretty easily guess how I know this.

[chuckg5]

i just went thru this with my 42' vagabond cutter ketch.
sea water got in thru the transmission cooler (corrorided copper tubing). replace the cooler of course then drain all fluid from transmission, put new fluid in - run engine and put transsion in gear for a few minutes. turn off engine an drain fluid again. did this 8 times until fluid is all red. still have to replace seals front an rear but it alway leaked a little anyway.

[Jeannius]

What is the tidal range where you are? I've done this job on Volvo saildrives, on the beach, between tides.

[49waves]

I've thought about beaching it to drain transmission fluid, but tidal range is baby in Ensenada. Like 3-4 feet. So, still have to figure out how to get all the bad stuff out of there...

[Jeannius]

Not quite enough range I think. Least I've done it in was 5ft range and then I was sitting in the water for half the time. That isn't a problem until you drop something!

There is a method of changing the oil while the boat is still in the water. At least that would buy you some time. Here's the link... http://www.yacht.de/schenk/trick/trick25.html The text is in German so you'll probably want to put it through Google Translate. The translation is good enough to work out what is happening.

[chuckg5]

49- what i ended up doing is buying (always) a vaccum oil hand pump
60bucks, that will suck out the oil from the small filler pipe.

[Cotemar]

There is an easy way to drain the SD20 Sail Drive oil when in the water, but it needs a little preparation.

Get a spare oil drain screw, good if you find a plastic one, or have one made from nylon or pvc, drill a hole inside and attach a hose.

When you want to change oil, be sure youre oil fill screw is really tight, dive, take out the original screw, as oil is lighter than water no oil will come out, as the top of the sail drive is closed, almost nothing will go in. screw in your nylon crew with the hose.

now you may suck all oil through your hose with one of those small manual pumps after opening the top screw.

Do not change the screw now, fill up with fresh oil, totally full, you will pump out that little overfilled later. This will prevent seawater coming in when you change the bottom screw. Do not forget to close the fill screw before ;-)

After removing the hose take out the excess oil from top, it is only a little bit, still clean enough for other applications on board.

Viola, so easy - at least when the sea is warm ;-))