Yanmar SD40 & SD50 "slipping" Saildrive Upgrade

[kenckar]

Originally Posted by Bruce Beard

I too, default to manufacturers specifications. If it helps, Yanmar says that both GL-4 and GL-5 is approved for use in an SD-50. ...
If you read the manual that came with my saildrive in 2005 it clearly specified that either standard was sufficient...

Bruce

The more recent manuals specify the QuickSilver.

I really think you're on to something with this. In my case though, slippage started at a few hundred hours and the cones and surfaces were glazed.

I suspect there are two causes going on. For young boats that have the problems it's the tolerances--for older ones, maybe wear is the bigger driver. Fascinating stuff.

[a64pilot]

Originally Posted by Bruce Beard

One more picture of the new boat and I'll be quiet...

We are truly enjoying the "dark side"!

Bruce

What Boat is this? I really like its lines, and it appears to have no exterior wood?

[Bruce Beard]

Originally Posted by a64pilot

What Boat is this? I really like its lines, and it appears to have no exterior wood?

That is an American Tug 395.
You are correct, it has no exterior wood!
After 25 years of beautiful exterior teak, all kept in lovely-to-look-at varnish, we were delighted to know that this boat would be “wood less”.
Of course we do still have some lovely wood to keep us happy...
Bruce

[SparkyDorado]

Originally Posted by Bruce Beard

The cone itself is bronze and it is considered a “consumable” part. The mating surfaces or the female parts as you refer to them are steel and are designed to last the life of the drive. As the bronze cone wears in diameter, it looses contact area that can be applied to the steel and it begins slipping.

The problem with GL-5 oils is that they are designed to help prevent wear in hypoid gear sets. Hypoid gears have long curved teeth that slide as they mesh, thus the oil must be slippery to help them survive. To achieve this, sulfur is added to the oils additive package. It is the sulfur that causes the problem with the cone clutch and leads to its early demise. The same problem exists with synchronizers in manual transmissions. If a GL-5 gear oil is used in a transmission that uses non sintered synchro rings (most European and Asian designs) the result is notchy shifting at first and ultimately the failure of the synchro.

When we purchased our Sabre in 2005, I began a regimen of service that included regular gear lube replacement with the Yanmar recommended Mercury Marine Quicksilver HP gear lube. As I mentioned in an earlier post, our first drive failed in early 2008. As it was the beginning of the season and time was short, we elected to simply replace the unit in order to get back in the water. After I made the swap, I disassembled the failed unit and immediately saw what had happened. Like the synchronizers I had once replaced in many transmissions that used the wrong oil, the wear in our failed drive looked extreme.

As I owned a repair shop that stocked a quality GL-4 gear oil of the correct viscosity for use in cars we serviced, I simply began using that oil in the new drive. Problem solved! We never had an issue with the cone again. I even began stretching the replacement interval as when I removed the cone it was essentially impossible to discern wear.

We changed nothing else about our use of the boat, it was the oil that made the difference.

By the way, lapping a cone is at best a temporary fix. They do wear and once the material is gone, it will slip.

I have never disassembled a Volvo cone clutch type saildrive but I do know that Volvo specifically recommends ATF or motor oil for their saildrive, that is a sure sign of a bronze cone...
Bruce

Volvo has had similar clutch issues, and around 2010 they issued a service bulletin that specifies the use of 10W-40 instead of ATF in its D130 saildrives. I think I even received a little sticker that read "10W-40 only!" that was meant to cover up the original "ATF only" sticker.

[Bruce Beard]

Originally Posted by SparkyDorado

Volvo has had similar clutch issues, and around 2010 they issued a service bulletin that specifies the use of 10W-40 instead of ATF in its D130 saildrives. I think I even received a little sticker that read "10W-40 only!" that was meant to cover up the original "ATF only" sticker.

That is exactly the solution used by Saab in the 80’s when they figured out that GL-5 oils were destroying their transaxels synchronizers.
Problem went away aside from the occasional incorrect filling afterwards. Then it was a synchro replacement.

My own experience with our SD-50 was a unit that failed in just 2 years when using their recommended synthetic GL-5 oil. The replacement is still working just fine 11 years and thousands of hours and a second owner later.
It just needed the correct oil.
Bruce

[ChrisseH]

Originally Posted by ChrisseH

Thanks again Bruce,

Not sure I can smell the difference between GL-4 and GL-5.

Had in mind to use the current cone as long as I can. Am not doing any long distance sailing and if/when the clutch starts to slip I can still use the drive for a while. The clutch will still engage, but not until you give enough throttle. Also, as I am mainly sailing I can always sail close to the harbor, drop the sails and reverse into the dock. But you are right in that the clutch sooner or later will start to slip.

Unless there are no strong arguments against, I will probably now try the Mobilube GX 80W-90.

Christer

Just wanted to inform that the Mobilube GX 80W-90 (GL-4) gear lube I started to use in my SD50 this spring (instead of the Quicksilver GL) has worked well the whole summer and fall. No tendency to slip despite of 125 more engine hours. After hauling I exchanged the gear oil to Mobilube GX again. The removed gear oil had during the summer become somewhat greenish, but contained perhaps still some remains of the old Quicksilver. The color of bare Mobilube GX is light brown.

Christer

[motion30]

when Mercruiser introduce their Bravo drive with a cone clutch, they had similar issues the solution was semi synthetic driveway oil. That is the Mercruiser bluish-green oil periods problem solved

[Bruce Beard]

Originally Posted by motion30

when Mercruiser introduce their Bravo drive with a cone clutch, they had similar issues the solution was semi synthetic driveway oil. That is the Mercruiser bluish-green oil periods problem solved

Not solved with a bronze cone!
Solved with a redesigned cone with an anti wear coating the Yanmar SD-40’s and SD-50’s don’t have.
No GL-5 synthetic or otherwise or you will destroy the cone.
Bruce

[AliaVita]

Has anyone sought Yanmar’s view on the oil issue? One of my SD50s is slipping again at 500 hours, and that’s 500 hours after installing a new cone, not lapping the old one. Rob

[Bruce Beard]

Originally Posted by AliaVita

Has anyone sought Yanmar’s view on the oil issue? One of my SD50s is slipping again at 500 hours, and that’s 500 hours after installing a new cone, not lapping the old one. Rob

They actually specify either a Gl4 or a Gl-5 oil. 500 hours is about what we got using Gl-5.
Never had another issue once we switched. I’d pull the cone at 600 hours and couldn’t tell it from a new one once we switched.
It was not my first time finding this Gl-4/Gl-5 confusion by a major manufacturer. I was in the automotive industry and a lot of major manufacturers had the same issue. It appears to be pretty well understood these days.

[ChrisseH]

Originally Posted by AliaVita

Has anyone sought Yanmar’s view on the oil issue? One of my SD50s is slipping again at 500 hours, and that’s 500 hours after installing a new cone, not lapping the old one. Rob

This is second hand information, but a Volvo Penta guy once told me that both Volvo's and Yanmar's smaller sail drives are actually manufactured by somebody else (in Volvo's case even the smaller engines are made by another company). According to him there are two main OEM manufacturers in this SD business. Unfortunately I no longer recall the names of these. However, as this (most probably) is the case it is likely that the ultimate SD expertise is not within the Yanmar organization. I agree of course that Yanmar still is responsible for the quality of the delivered entity.

And I believe Bruce when he says that it is easy to fall into the trap and specify a gear lube with superior lubrication properties forgetting that GL-5 oil is both corrosive and too slippery for a clutch cone made of brass.


Christer

[AliaVita]

Originally Posted by Bruce Beard

They actually specify either a Gl4 or a Gl-5 oil.

This is not quite accurate. See the attached for mating the SD50 with the 4JH4 engine which is what we have. They are very specific that only Quicksilver will do. I’m guessing that they specify a different lube for the 75hp engine because the lesser grade may cause issues somewhere else? What do you reckon?

Rob

[Bruce Beard]

Originally Posted by AliaVita

This is not quite accurate. See the attached for mating the SD50 with the 4JH4 engine which is what we have. They are very specific that only Quicksilver will do. I’m guessing that they specify a different lube for the 75hp engine because the lesser grade may cause issues somewhere else? What do you reckon?

Rob

You are correct if you have an SD-50T, that sail drive uses a cone that is coated with a sintered finish that protects it from the GL-5.
My guess is that in the case of the larger engine/higher torque output they are concerned with wear in the gears in the lower unit. The GL-5 would be of benefit there.
If the cone is not a coated cone, don’t even think about the GL-5.
Our SD-50 had a sticker that was obviously attached during its manufacture that specified GL-4/GL-5.

[AliaVita]

Originally Posted by Bruce Beard

You are correct if you have an SD-50T, that sail drive uses a cone that is coated with a sintered finish that protects it from the GL-5.

We are assuming of course that when I had both cones replaced at 1200 hours in the BVI, just 500 hours ago, that the Yanmar agent there replaced our SD-50T cones with SD-50T cones and not SD-50 cones! Do you know if they would look any different? I need to check the part numbers as I carry two new cones on board.

[Bruce Beard]

Originally Posted by AliaVita

We are assuming of course that when I had both cones replaced at 1200 hours in the BVI, just 500 hours ago, that the Yanmar agent there replaced our SD-50T cones with SD-50T cones and not SD-50 cones! Do you know if they would look any different? I need to check the part numbers as I carry two new cones on board.

Best I can do on the fly is show you an example of an uncoated cone as used in the SD-40/SD-50 type. The coated cones have an obvious dark face on the cone.