Help needed: Transmission problems?

cardude01 said:

And now my autopilot is hunting around like a drunken sailor. I swear. If it's not one thing....

When I was anchored the barges pushed me into the mud once and the rudder bumped lightly. Is that a clue?

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Since you were just working on the transmission, make sure you didn't inadvertently leave a toolbox or object near the compass. I once did that and it took me a week to find a wrench I left a few inches from the compass.

If the steering feels good and the boat steers well manually, it's probably not the rudder. If when you hit the mud, the rudder did swing violently, maybe the rudder position sensor could have become disconnected or something like that. The troubleshooting section in your owner's manual will probably get you to the right answer. Sometimes, re-running the dockside and underway calibration and self-testing will reset the unit or reveal the problem.

I thought I had a stuffing box leaking like crazy. Pulled in to the marina I was going to store the boat at for a fee weeks and they said the shaft tube was leaking.

I never saw the repair happen since I was back in Texas. Is it possible they misaligned things?

LarryM said:

Since you were just working on the transmission, make sure you didn't inadvertently leave a toolbox or object near the compass. I once did that and it took me a week to find a wrench I left a few inches from the compass.

If the steering feels good and the boat steers well manually, it's probably not the rudder. If when you hit the mud, the rudder did swing violently, maybe the rudder position sensor could have become disconnected or something like that. The troubleshooting section in your owner's manual will probably get you to the right answer. Sometimes, re-running the dockside and underway calibration and self-testing will reset the unit or reveal the problem.

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Ok. Thanks. I'll try when at anchor. Too hard in this narrow canal with all these barges to calibrate anything.

A few years ago my autopilot started doing something similar I called raymarine they helped me troubleshoot over the phone turned out the rudder feed back sender, mounted near the steering cylinder, was bad. It was an easy and not too expensive a replacement part fix.
At least you'll be able to proceed OK without the AP.
Good luck!

My autopilot is fed heading by a fluxgate compass. Whenever I pass within 10' of anything steel (bridge, barge, ferry). Anything the heading sensor goes wild. Swings about 20 degrees each way.

Regarding the shaft, seems coincidental. The condition of the gear oil is more suspect. Do you have a manual? Look for a clean out port, a screen or a filter on the tranny. If yours has a clean out plug, they often have a built in magnet. Make sure to wipe that off and inspect for metal shavings, chips.

cappy208 said:

My autopilot is fed heading by a fluxgate compass. Whenever I pass within 10' of anything steel (bridge, barge, ferry). Anything the heading sensor goes wild. Swings about 20 degrees each way.

Regarding the shaft, seems coincidental. The condition of the gear oil is more suspect. Do you have a manual? Look for a clean out port, a screen or a filter on the tranny. If yours has a clean out plug, they often have a built in magnet. Make sure to wipe that off and inspect for metal shavings, chips.

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Ok. Will check out tranny again at anchor.

I do not know if your tranny requires it ,

but some require the shaft be able to move back or fwd a 1/2 inch to engage in gear.

You might ask the tranny folks and disconnect the shaft to see if you have the shaft motion space if its required.

The prop shaft is able to move forward and aft through the stuffing box.

Is that what you mean?

cardude01 said:

The prop shaft is able to move forward and aft through the stuffing box.

Is that what you mean?

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Not quite, but if it moves through stuffing box, it also moves in transmission. Reading your posts, you mention going aground. It is possible that when you got shoved into the mud that the prop got shoved into the mud too. This may have strained, stressed the thrust bearings /washers in the tranny. Does your manual state how much end play the tranny output shaft should have? Measure the forward and aft movement you can push/pull the shaft. What's the total distance? Once you get that number, call a mechanic who knows marine transmissions. Or call the tranny company.

The prop is way up from the bottom of the keel. No way it got impacted by the mud.

cappy208 said:

Does your manual state how much end play the tranny output shaft should have? Measure the forward and aft movement you can push/pull the shaft. What's the total distance? Once you get that number, call a mechanic who knows marine transmissions. Or call the tranny company.

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This is the diagram of the output shaft. It rides on tapered roller bearings which are actually set up with a slight preload (like wheel bearings on a car). There is supposed to be NO end play in the output shaft. The shims in the diagrams are used to move it back and forth to adjust its engagement backlash with the drive gear on the clutch shaft.

If there is measurable end play in the output shaft, you can see clearly from the diagram that either the tapered roller bearings are worn, or the outer races have moved in the transmission housing from shaft impact, gear, bearing or case failure.

I'm sure that as the transmission wears, some small amount play could develop here, but repeated contact with Yanmar and authorized repair shops have said ideally, no play should be felt. When pressed for some kind of practical limit on play if it does exist, they would not comment.

On my last transmission, I found .030" end play after a full power crash shift, and almost everyone recommended repairing it before it got worse and ruined the entire transmission. One shade-tree supposed 'expert' recommended that I keep running it and see if it got worse, and oh, to keep an eye on the oil.

Do check with the experts and see what they recommend. The above is just my experience with Kanzaki transmissions.

cardude01 said:

The prop is way up from the bottom of the keel. No way it got impacted by the mud.

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A keel can slice through river mud like a hot knife through butter exposing the prop and rudder to grounding.

I'm still puzzled as to how the transmission/gear oil can get bad without something wrong there. Are you sure right gear oil was used.

Don't ask me how I know, but a piece of iron left near the AP compass can indeed create a need for recalibration,

Last but not least did your issues begin after repairs by locals? Interesting post, kinda like "who is on first."

Bill: I'm trying to remember what the shaft repair actually was at Indiantown. Didnt they pull it and reglass the shaft tube at the stern exit. It's not likely but it's possible they got the tube a bit off center, causing a mis-alignment. I still think the original seller didn't ever change the tranny oil and most of the issue was just the cone swimming in crud.

Yeah, that's what they did to the shaft tube.

Only strange thing is I had a mechanic change the main engine and transmission oil right after I bought the boat in Fort Lauderdale. I guess there's a chance he didn't actually change the transmission oil, but it was on my invoice.

I have no idea at this point.

Hi cardude1.

I may have missed it but was the problem with shifting gear only while the engine was running, that is did you try shifting gears with the engine off.

I used to drive / master ferries which had a cone clutch and they were a bitch, they used to lock up in forward and much banging of the the gear wheel was required to bump them free, these were operated by winding a wheel forward or back to engage the direction you wanted to travel.

A bike chain used to wind them in or or out to select the required gear, they were lubed with a grease gun though and not oil. I am talking old boats back in the 70s running with two cyclinder Kelvins. Ancient equipment even back then.

Good Luck.

Regards.

David.

Not sure what you have for control cables? check the control cables, this happened to me recently. Luckily it was a $40 morse cable and not a $4000 tranny.

Also, CD I think the 'shoved in them mud is a red herring'. You said you were anchored. I assume this means the engine wasn't running. Then there should be no issues with the tranny from that. Bent wheel maybe, but not a running gear issue.

There is (at least on the Kanzaki tranny documentation I found) an oil drain plug WITH a magnet. Do your self a favor and drain the oil out. And check the magnet. Sucking the oil out does not allow free flow of any debris out of a closed vessel.


http://www.marinedieselengineering.com/md/wp-content/uploads/2011/01/MD-TTM50A_Service-Manual.pdf


I don't know your particular model tranny, but here is a Kanzaki service manual. Specifically look at page 27. It shows the oil strainer parts, an exploded view on how to remove them and clean them, and the magnet plug.


Do as they say and catch the oil coming out, sift through it and look for metal shavings and bits. I hope that you don't find any. But I bet this will confirm or eliminate mechanical issues.

cappy208 said:

@ Larry: Do you have any documentation of the oil drain plug? Specifically does it have a built in screen filter? Or is there a clean out magnet on this model Tranny?

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Cappy,

My service manual is for the Marine gear model KM4A (Angle drive), not the KM4A2 variant. As you can see below, there is no reference made to a 'magnetic' drain plug.

On my KM4A, and every other KM series I have ever seen, there was just a simple steel drain plug without a magnet. There are no screens or filters as there are no pumps in these transmissions. The lubrication is by 'splash' method with the gears slinging the oil throughout the case and gears.

One good thing is that the drain plug is situated horizontally at the lowest part of the transmission case. When I was troubleshooting one of mine, I used a small pencil magnet tool and inserted it into the drain hole. I was able to slide it around the bottom of the case to attract magnetic particles, and easily extract it for examination.

These bronze cone clutches in normal service can be pretty dirty because of the material that wears off the cones each time they engage. I recently installed a factory new unit and changed the oil at 25 hours. I was shocked at how dark it was and even found some steel shavings and bits in the oil. I called Yanmar immediately. They said it was completely normal as the parts were just wearing in, and to change it a couple of times in the first hundred hours or so. I submitted the second oil change (still dark but no steel) to Blackstone labs and they said it was just perfect. That, by the way, is why I suggested that Skipperdude try to strain his drained oil through clean cloth to look for any steel bits from failed bearings or gears. Otherwise, it is hidden in the dark oil and might not be noticed. I was thinking that if there were no further signs of damage in the oil, it might be relatively safe to continue the trip, even with some endplay in the output shaft.

It is hard to troubleshoot long distance and I would hate for my guesswork to contribute to Skipperdude's facing a failure at some horrible moment on the way back.

To get more accurate info I guess the sleeper question would be..... What model transmission is this? CD?

cappy208 said:

To get more accurate info I guess the sleeper question would be..... What model transmission is this? CD?

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Cappy,

In Skipperdude's original post he stated "It's a Yanmar KM4A2 transmission."

Dudes, dudes, dudes. Way too many dudes here.
It's cardude, not skipper dude.

TOAD Marine Supply


Item NO 21


Item NO 11


Anywhere I look I can't find the A2 variant. But both A and A1 show this magnet plug, and reference a case strainer. Larry, I agree with your swabbing of the plug area. However that has never been confirmed by CD (SD is in Alaska!) Just trying to point out the possibility to have a clean out drain being better than the mentioned "sucking out the oil" as an investigative procedure. And the magnet (whether built in or swabbed as you did) is an excellent way to eliminate or confirm metal bit and pieces in the sump.

Sorry. Family showed up. Busy.

It's a KM4a2.

I'm going to wait to do any more work to the trans until I get back. Seems like every time I touch it something else breaks.



My current fix


?

http://www.yanmarmarine.eu/theme/yanmarportal/uploadedFiles/Marine/productDownloads/Pleasure%20-%20operation%20manual/Operation%20Manual%203JH5_4JH5_4JH4_TE_4JH4_HTE_4JH4_HTE1(0AJHM-M00201).pdf


ON page 114 is direct reference to 'centrifugal pump' on transmission. Thus, this does have a strainer to clean. Regarding whether it has a magnet drain plug is pretty superfluous. It 'should' have one. If not, then the excellent idea of swabbing into the oil plug hole with a magnet is a great idea to look for debris.


CD. After your comment about 'you were billed for a nonexistent tranny fluid change' I would definitely suspect lack of maintenance is exacerbating this issue. So, it's not just a change fluid. There's more that needs to be done to at least eliminate some of the possibilities which could cause the stalling.

Excellent info. Thanks.

It's not stalling anymore, but I definitely want to drain it from the bottom and get any addition crud out of there, and clean the screen.

cappy208 said:

http://www.yanmarmarine.eu/theme/ya..._4JH4_TE_4JH4_HTE_4JH4_HTE1(0AJHM-M00201).pdf


ON page 114 is direct reference to 'centrifugal pump' on transmission. Thus, this does have a strainer to clean. Regarding whether it has a magnet drain plug is pretty superfluous. It 'should' have one. If not, then the excellent idea of swabbing into the oil plug hole with a magnet is a great idea to look for debris.


CD. After your comment about 'you were billed for a nonexistent tranny fluid change' I would definitely suspect lack of maintenance is exacerbating this issue. So, it's not just a change fluid. There's more that needs to be done to at least eliminate some of the possibilities which could cause the stalling.

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Cappy,

Great info. Looks like the KM4A2 was upgraded from splash lubrication to forced lubrication with the addition of a centrifugal pump and a magnetic drain plug, but it is still a cone clutch transmission. I have yet to find either a parts or service manual for the A2 version of the KM4 gearbox. Yanmar really tries to limit access to their approved dealers and service organizations.

As for the filter, it looks like only the KMH4A transmission has a filter. It has a hydraulic clutch with a trochoid pump, filter etc. The illustration on page 73 (PDF page 81) of that manual shows the filter location and instructions. This is not Cardude's transmission though.

Regardless, all of the posts relating to checking the oil for debris are still valid. That magnetic drain plug is a plus.

cardude01 said:

Sorry. Family showed up. Busy.

It's a KM4a2.

I'm going to wait to do any more work to the trans until I get back. Seems like every time I touch it something else breaks.

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My current fix
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Cardude,

I hate to even mention this, but it is important. The Kanzaki dipsticks are notorious for breaking, and they are expensive. Worse, plugging the dipstick hole with a solid object is not recommended. The original dipstick contains a vent hole that keeps the transmission from pressurizing when it is hot. In fact, the Kanzaki repair manuals even state "There is a small clearance between the dipstick and the inside of the dipstick tube. A small hole in the dipstick works as a breather." If too much pressure builds up, the oil can be forced out through the seals and gaskets.

A quick Google search for "Yanmar broken dipstick" will bring up posts from many unhappy owners.

If you must leave before getting a replacement, please drill a small hole in your plug to vent the transmission.

At least your dipstick tube did not fall into the transmission like it has done for some!

Bob Atkins over at the Catalina 42 forum has come up with a fix for the original plastic cap. It costs a little more but fixes it forever.

Here is a link to his posting.

And here is the fix. I think in your case, you would just use the cap and your original dipstick tube.

After I started googling for a new dipstick I ran across all the problems folks were having and realized the dipstick has a breather.

I did have to take off with my wooden plug, but it's definitely not air tight. Some oil is weeping past so it's breathing, but it's also making a mess. I'm stopping every hour to 30 min to check the trans fluid and I'm not losing much.

Kind of a pain but that plug all I could come with on short notice. It's actually one if those plugs in case a seacock fails.

Hi cardude1.

If your box does not have a magnet on the drain plug then you can easily pull apart an old speaker and prise the round magnet out of it and simply place it on the outside of your box near the drain plug.

This will not get the shards / debris out of the box but will catch them untill you pull the pan off it in the future. It will remove these bits from circulating around the inside of your box. This can be done on any engine with a steel sump and costs next to nothing.

Regards.

David.