Engine oil is 100, transmission?

Rick D · Nov 3, 2010

My manual says with each motor oil change, although the oil is perfectly clean every time I do it. I do it anyway since it's a nothing job while I'm at the engine and filter anyway. I did take some sandpaper to the dipstick to rough it up since I could not tell the level easily. In fact, I have done the same thing with the cars.

PS: The boat averaged 138 hours/year over the 16 years since it was splashed and I have owned it eleven of those years.

rardiH36 · Nov 3, 2010

My Seloc manual, which covers the GM series specifies every 250 hours for the oil in the clutch/transmission housing. I have an official Yanmar service manual for the GM series, which was left with the boat by the PO (even though the boat was installed with QM series engine!). I can't find the recommended interval anywhere in the Yanmar Manual however. It's a three-holed binder type. Maybe the PO removed the maintenance summary chart and forgot to put it back. As with RickD, every time I've changed the transmission oil, it perfectly clean.

Rick said:
... Funny, how you guys can go a season without putting a hundred hours on your engine ....

In my case, its because the motor is used primarily for getting in/out of the berth and the channel to the SF Bay's open water. Then wind power takes over for the most part. Engine use for each outing probably averages 45 minutes. I've put on just under 300 hours over three years of ~2 times per week use.

Lee Coller · Nov 3, 2010

I change mine every time I change the oil since it is so easy to just drop the suction tube into the transmission and it uses the same oil.

As to how I don't put a hundred hours a year on the engine, my boat has a couple big white pieces of fabric that allow me not to use the engine. Seriously, having done Catalina to San Diego I know how you feel, the wind is either on your nose or stern. From Redondo its a reach, so we can frequently sail.

Benny17441 · Nov 3, 2010

The transmission is one place where synthetic oil shines. It's resistance to heat and viscocity breakdown and the clean environment of a sealed transmission gives it the qualities to perhaps last 10 years. Once a transmission is broken in and the ocurrence of metal shavings is reduced to a minimum that oil can stay clean and in good condition for a long time. I have not changed the oil in my transmission for the past three years and look forward to keep using it for a few years more. I do check the oil level every 90 days and rub some between my thumb and forefinger to insure viscocity is good. Besides the good qualities of the oil it helps the fact that I may only barely put 100 hours under engine power a year. For the engine I do not use synthetic as it is going to get dirty anyways and will end up changing it at least three times a year. The 3 month or 3000 miles guideline for automobiles is a myth sustained by the oil industry and service garages. The largest cause of oil breakdown is heat and not necessarily dirt or combustion derivatives. With all oils being much better these days the number of oil changes can be safely reduced. I now handle the task when it seems convenient rather than keeping up with a strict schedule which ain't gonna do something for me.

Bill Roosa · Nov 3, 2010

Don't use synthetic oil in a trany

While synthetic oil is great at storing sludge from combustion in suspension it does not have what transmissions need, extreme pressure lubricating properties.
In fact it stinks at EP. Gears absolutely need EP and unless you have a multi-plate clutch in there too (most don't) I'd recommend (gasp) 90 weight gear oil.
Your change interval is going to be seasonal for most of us as the oil load up with water from lack of use before anything else.
You change gearbox oil in a car at 50k miles. If I average 30 MPH that would mean 1667 hours of operation.

higgs · Nov 3, 2010

I have never changed trans oil in any of my cars and never had a problem. I have not done it on the boat in 5 years. Most of the guys around here don't change it.

GKuffner · Nov 3, 2010

Rick,

Thanks for the tip on using sandpaper to rough up the Transmission dip stick. Not being able to read it was driving me nuts.

Gary
Glory Days, C309

Maine Sail · Nov 3, 2010

My gear box takes 1 quart and requires about three minutes of my time to change it. I have seen to many gear boxes destroyed by lack of maintenance, especially Hurths. Changing it is a no brainer for the $2.49 and 3 minutes. I also change the "lifetime" fluid in my automobiles because none of the manufacturers have been willing to define "lifetime". BMW has gone so far as to remove the dipstick for the transmissions.

"Lifetime" for these manufacturers seems to be their warranty life not how long you'll actually keep the car.

Is lifetime 100k, 200k, 300k, 400k...? Just changed the trans fluid in my 2009 Toyota last week. In my wife's Pilot I drain & fill the transmission, about 3 quarts comes out, with every oil change. Even at 140k the trans fluid looks as good as it comes out of the bottle...

A moment of inattention of leaving the gear in forward on some gear boxes, while sailing, can shed metallic shavings into the oil/ATF. When the engine runs the next time it makes it to the clutches and various bearing surfaces and can cause wear.

This is a thrust washer from a Hurth and the fluid that came out of it was pure black. It should be flat and the fluid should have been cherry red...