Yanmar SD40 & SD50 "slipping" Saildrive Upgrade

[AliaVita]

Thanks Bruce, very useful. I have just checked my invoice from 2015 and I now have the SD40/50 cones? Brilliant! Having said that, the SD-50Ts both failed at 1200 hours but I doubt had been lapped before that. I bought the boat with 600 hours on.

[Dulcesuenos]

Brett and Gideon from sailing vessel panache have a kit I believe is supposed to permanently cure the need to ever mess with the clutches again on the sd 50,
Their email is panache5000@yahoo.com

[Panache5000]

A couple of issues/clarifications;
1. The Yanmar recommended Quicksilver High Performance Gear Lube is a SAE90 API GL4 Oil. Check out the label on the back of the quart container to verify this.


2. The Drive Cone listed in the Yanmar Parts catalogue has 2x part numbers ; 196326-04250 and 196326-04251 and BOTH numbers are listed for the SD40, SD40-4T, SD50 and SD50-4T.



3. The main REASON why the Cone Clutch starts slipping is too much up/down free play on the Upper Vertical shaft. This play, combined with the limited travel of the Selector, allows the Shifter to retract away from the Drive Cone before the male and female Cone surfaces have made firm contact.


4. The CAUSE of the up/down play is due to excessive initial setting-up tolerance and wear of the standard Yanmar Copper thrust washers, as well as wear on the lower C- Clips and Lower Collar.


5.The Upgrade Kit replaces the Copper washers with Thrust Bearings allowing and maintaining close setting up tolerances, and now also replaces the lower C Clips with a Taper Lock system.

Contact me on; saildrives@yahoo.com for more information on this.



6. The correct Oil to be used is most important, as discussed on this forum, and any glazed oil residue in the small grooves on the Drive Cone will reduce positive Cone Surface mating.


7. It is important to use an Oil that readily Emulsifies, and stays emulsified (for as long as possible!) to keep any water ingress in suspension, rather than separating and causing corrosion to the Lower Drive components.
It is also important to change the Emulsified oil ASAP, and not to leave it unattended for an extended period. The water and Oil will eventually separate.


If I can be of any further assistance in this regard, contact me on saildrives@yahoo.com

[Bruce Beard]

Originally Posted by Panache5000

A couple of issues/clarifications;
1. The Yanmar recommended Quicksilver High Performance Gear Lube is a SAE90 API GL4 Oil. Check out the label on the back of the quart container to verify this.


2. The Drive Cone listed in the Yanmar Parts catalogue has 2x part numbers ; 196326-04250 and 196326-04251 and BOTH numbers are listed for the SD40, SD40-4T, SD50 and SD50-4T.



3. The main REASON why the Cone Clutch starts slipping is too much up/down free play on the Upper Vertical shaft. This play, combined with the limited travel of the Selector, allows the Shifter to retract away from the Drive Cone before the male and female Cone surfaces have made firm contact.


4. The CAUSE of the up/down play is due to excessive initial setting-up tolerance and wear of the standard Yanmar Copper thrust washers, as well as wear on the lower C- Clips and Lower Collar.


5.The Upgrade Kit replaces the Copper washers with Thrust Bearings allowing and maintaining close setting up tolerances, and now also replaces the lower C Clips with a Taper Lock system.

Contact me on; saildrives@yahoo.com for more information on this.



6. The correct Oil to be used is most important, as discussed on this forum, and any glazed oil residue in the small grooves on the Drive Cone will reduce positive Cone Surface mating.


7. It is important to use an Oil that readily Emulsifies, and stays emulsified (for as long as possible!) to keep any water ingress in suspension, rather than separating and causing corrosion to the Lower Drive components.
It is also important to change the Emulsified oil ASAP, and not to leave it unattended for an extended period. The water and Oil will eventually separate.


If I can be of any further assistance in this regard, contact me on saildrives@yahoo.com

That is an interesting assessment of the issue.
A lot of years rebuilding gearboxes in European automobiles and a couple of SD-50 autopsies leads me to believe that your conclusion is more of a treat the symptom fix than is necessary though.
By switching to a correct GL-4 oil we never again had any issues in a lot of hours use. No shims necessary. Of course I was beginning with a new saildrive at that time and not trying to combine worn parts with new.
The wear in the original units parts was amazing in 600 hours using the US distributors recommended GL-5. That is why I decided to simply replace the unit at that time. Cost of replacement parts was close to the price of a new unit.
Whatever works though...

[petervl]

As we all know from the official documentation, Yanmar recommends Quicksilver High Performance Gear Lube for the SD50 in particular. This is a GL-4 oil, not GL-5. I’m attaching a picture of the container as evidence here.
I’m wondering what this “US distributors recommended GL-5” is all about. Apparently something else than Quicksilver HP Gear Lube as this is not a GL-5 and against the official Yanmar recommendation or am i missing something here?

[Bruce Beard]

Originally Posted by petervl

As we all know from the official documentation, Yanmar recommends Quicksilver High Performance Gear Lube for the SD50 in particular. This is a GL-4 oil, not GL-5. I’m attaching a picture of the container as evidence here.
I’m wondering what this “US distributors recommended GL-5” is all about. Apparently something else than Quicksilver HP Gear Lube as this is not a GL-5 and against the official Yanmar recommendation or am i missing something here?

As I no longer own my boat that had the SD-50 and the photos I took in those days are not part of the cloud I can’t show the decals that came on the unit now.
Both of my SD-50 units came with decals showing that GL-4 or GL-5 grade oils could be used. The Mercury Quicksilver lube Yanmar recommended in those days was in fact a synthetic GL-5 oil.

I always assumed that the US distributor attached the decals but I have no way of knowing for sure. I do know that in Europe, there was a greater awareness of the difference in GL oil ratings.

When looking for a GL-4 lube here in the US, it is difficult to find one that also is not rated GL-5 as the GL-5 spec has language that says something like “meets or exceeds...”. Of course that is true if you are speaking about gears and not friction devices like a cone clutch. This the confusion...

[Bruce Beard]

I have just been looking online at some of these oils. It appears that there have been changes to the Quicksilver oil line. Are they no longer associated with Mercury?
The oil that Yanmar used to recommend does not appear to be available any more. Just be careful that whatever oil you select is not rated for GL-5 and I’d guess you are good to go.

[Captain Bill]

I had SD-40s and got about 3000 hours on my cone clutches before I had any slippage issues with my drives. I probably should have replaced the clutches at that point because I only got about 200 more hours out of them before they started slipping again after lapping. The secret to 3000 hours is left hand props. Left hand props use the upper clutch for forward and the upper clutch is not affected by the thrust washer wear issue. I used Quicksilver High Performance Gearlube the entire 3000 hours. Even though I replaced the thrust washers and carefully adjusted the tolerances the reverse gears (bottom clutch) started slipping again at 200 hours engine time. It's pretty clear the clutch was worn out. I'm not saying the oil argument is wrong, but I would like to know how I could have gotten 3000 hours out of my upper cone clutch if that was the primary problem.

[Bruce Beard]

Originally Posted by Captain Bill

I had SD-40s and got about 3000 hours on my cone clutches before I had any slippage issues with my drives. I probably should have replaced the clutches at that point because I only got about 200 more hours out of them before they started slipping again after lapping. The secret to 3000 hours is left hand props. Left hand props use the upper clutch for forward and the upper clutch is not affected by the thrust washer wear issue. I used Quicksilver High Performance Gearlube the entire 3000 hours. Even though I replaced the thrust washers and carefully adjusted the tolerances the reverse gears (bottom clutch) started slipping again at 200 hours engine time. It's pretty clear the clutch was worn out. I'm not saying the oil argument is wrong, but I would like to know how I could have gotten 3000 hours out of my upper cone clutch if that was the primary problem.

Interesting. We had a left hand propeller and lost our first drive in just 600 hours.
I am curious, how are the redesigned saildrive units holding up?
Has Yanmar figured it out?

[ChrisseH]

A few comments to the most recent discussion:


1. It came as a surprise to me that there also is GL-4 rated Quicksilver gear lube. In Finland I have (at least so far) only found GL-5 rated Quicksilver GL.



2. I understand that the cone clutch can start to slip if the up/down free play of the vertical shaft is large, but in my case the bronze washers had worn less than 1/10 of a millimeter after 1200 engine hours. And if such a small play would be the cause the slipping then the entire clutch design is poor...


Christer

[Bruce Beard]

Originally Posted by ChrisseH

A few comments to the most recent discussion:


1. It came as a surprise to me that there also is GL-4 rated Quicksilver gear lube. In Finland I have (at least so far) only found GL-5 rated Quicksilver GL.



2. I understand that the cone clutch can start to slip if the up/down free play of the vertical shaft is large, but in my case the bronze washers had worn less than 1/10 of a millimeter after 1200 engine hours. And if such a small play would be the cause the slipping then the entire clutch design is poor...


Christer

I still do not believe that it is a thrust issue. My saildrive had thrust that was in spec at the time it failed.
What baffles me about all of the talk about thrust is that the cone is driven into the mating surface of the gear/clutch by a screw action. It is pretty positive!
In any case, the correct gear oil is imperative.
Remember that this conversation is for the SD-40 and SD-50 units not the SD-50T that had the coated cone.

[Captain Bill]

Originally Posted by Bruce Beard

Interesting. We had a left hand propeller and lost our first drive in just 600 hours.
I am curious, how are the redesigned saildrive units holding up?
Has Yanmar figured it out?

A some of you might know I replaced my SD40's with SD60s about 3.5 years ago(just before Panache released his kit). I had a reverse drive failure at about 1200 hours on the port engine that was attributed to a known defect and both upper sections were replaced under warranty. Oddly, a guy I met that used to work for ZF told me that the ZF SD10 had this same defect and he had been trained as a field technician to repair said defect in the field. Yanmar takes a different approach and sends you a remanufactured upper section and does the repair in a proper machine shop. The defect is an improperly ground ramp angle on the forward gear and usually shows up in less than 100 hrs. Again because I use left handed props I use the "Reverse" gear to go forward and since the problem only exists on the "forward" gear I didn't see the problem right away. How much time does one actually spend in reverse? The new upper sections appear to be working just fine, though both prop shaft seals leaked within a year of replacement. I have been told that the SD60 ramp angle problem has been corrected current units and it only affected a known series of early serial numbers which is why they replaced the upper unit of my starboard drive which had not yet failed.

The clutches, which are multidisk rater than cone clutches, have lasted 2 years and 1200 hours on one set and 1.3 years and 700 hours on the second set. Is this better than the SD40/50s? It's hard to say with such a small sample.

[Bruce Beard]

Originally Posted by Captain Bill

A some of you might know I replaced my SD40's with SD60s about 3.5 years ago(just before Panache released his kit). I had a reverse drive failure at about 1200 hours on the port engine that was attributed to a known defect and both upper sections were replaced under warranty. Oddly, a guy I met that used to work for ZF told me that the ZF SD10 had this same defect and he had been trained as a field technician to repair said defect in the field. Yanmar takes a different approach and sends you a remanufactured upper section and does the repair in a proper machine shop. The defect is an improperly ground ramp angle on the forward gear and usually shows up in less than 100 hrs. Again because I use left handed props I use the "Reverse" gear to go forward and since the problem only exists on the "forward" gear I didn't see the problem right away. How much time does one actually spend in reverse? The new upper sections appear to be working just fine, though both prop shaft seals leaked within a year of replacement. I have been told that the SD60 ramp angle problem has been corrected current units and it only affected a known series of early serial numbers which is why they replaced the upper unit of my starboard drive which had not yet failed.

The clutches, which are multidisk rater than cone clutches, have lasted 2 years and 1200 hours on one set and 1.3 years and 700 hours on the second set. Is this better than the SD40/50s? It's hard to say with such a small sample.

So the new unit is a ZF?
They are bright people and I’d bet that they will be just fine.
It is kind of interesting that they had issues out of the gate actually. I’d have bet that they had the design down pat. Who’d have thought?
Very interesting!!!

[petervl]

Originally Posted by Bruce Beard

I have just been looking online at some of these oils. It appears that there have been changes to the Quicksilver oil line. Are they no longer associated with Mercury?
The oil that Yanmar used to recommend does not appear to be available any more. Just be careful that whatever oil you select is not rated for GL-5 and I’d guess you are good to go.

The High Performance Gear Lube is still there: https://www.quicksilver-products.com...ase-lubricant/

Regarding the oil type recommended by Yanmar for SD50 there has been a change in 2009. Before 2009 the SD50 Operation Manual (dated 2004) mentions "API GL4 or GL5 and SAE 80W90 or 90 or Quicksilver High Performance Gear Lube" for the SD50 and Quicksilver HP Gear Lube for the SD50-4T. Starting with the 2009 version of the SD50 Operating Manual Yanmar specifies only Quicksilver HP Gear Lube for the SD50 - similar to the SD50-4T. See sections attached. This might clarify why some of us see the generic reference to GL4 or GL5 on the label attached to older sail drives. Mine is from 2009 and has the label corresponding to the specification in the 2009 manual.

[fortyninegroup]

I have an SD-50 with ~3000 hours on it. 200 of those are mine.

It started slipping and I ended up pulling the clutch - a beast of a job, as the shims had been spun outside the clutch housing on the upper shim. I ended up using a puller to remove the assembly, it did not just lift out, the way it does in the video referenced earlier - I followed that process however ( and have the Yanmar manual). The shims were wrinkled, so I measured where I could and replaced the cones, thrust washer, and shims. The stamp for the offset to calculate the shim thickness that is supposed to be on the base of the shifter is just not visible. There are signs where someone working on it previously has scraped the shifter base.
Today we went out and above 2,000 RPMs I can still detect that the prop speed is not increasing with the increase in engine RPM at above 2,0000 RPM. I'm also getting an occasional shrill sound that sounds like slipping. The SD-50 is pretty good up to 2,000 RPM. Reverse is also good. Looking for any advice, as this is the most thoughtful and informative thread I've seen on this SD-50 slippage issue. Thanks in advance.