[Norstar]

We have developed a leak on our rear oil (transmission) seal. The fluid leaks out and then sprays 360 degrees in engine space when shaft spins! Yikes!!!
Does anyone have any experience replacing the rear seal and O ring without pulling the transmission? Looks pretty tight down there with not much room to work. Can get the coupling apart but access to seal is limited. We have a 1990 PSC 34 with the Yanmar 3HM35F engine and a Kanzaki KBW10 gear. Our gear takes ATF fluid and there is no noticable loss of fluid on the dipstick at this point. Caught it early on so transmission ok so far. Just starting our charter season so timing not good but do not want to run like this until repaired!!!

Thanks,

John Schwab
PSC 34 #201
Norstar

 

[jimgo]

John, with as small as the transmissions are, is there a reason you don't want to remove yours? As you point out, there isn't much room to work in the engine "room"; why not make things a little easier on yourself? Granted, you may have to realign the engine once the transmission is back together, but that doesn't seem like it will be THAT difficult.

 

[wsmurdoch]

We have removed (and replaced) the transmission on our 3HM35F/KBW10.

(By my now 7 year old memory)

Break the prop shaft coupling and slide the shaft back a little
Disconnect the shift cable (mark the hole in use)
Take the top nuts off the back engine mounts
Jack up the back of the engine with a small jack under the oil pan
Slip some wood scraps under the engine and rest it on them wedging it in place
Unbolt and remove the transmission

It was not a particularly hard thing to do although the splined shaft was hard to withdraw and we ended up unbolting the damper disk from the flywheel.

Bill Murdoch
1988 PSC 34
Irish Eyes
[in George Town for the Family Islands Regatta]

 

[DaveMancini]

Hi John,

We had ours replaced in Port Angeles on the same transmission without pulling it for $65. It took the guy about 30 minutes. You will need a special wrench to get the trans coupling nut off. The seal was cheap. I don't recall an O-ring. I have drawings and part numbers (seal and wrench) if you want them. The guy showed me how to do it so I can handle the job myself if needed in the future.

Dave Mancini
PSC34 #305 Swan

 

[mondofromredondo]

Had mine replaced on my 3GM by a mechanic. He took the entire tranny out and brought it to his shop. It looked like a big job doing all that and cost me about $750.

Dave's solution sounds so less painful.

 

[Norstar]

Dave, I was hoping to accomplish without pulling the transmission if possible like in your case. I have the seal and O ring on the way. Had a good parts diagram in the engine manual. The O ring goes in after coupling and lock nut according to the diagram. Only about $7 worth of parts! The special tool to remove the coupling nut will be required if you can send me some info on that. I'll give it a shot and see how much trouble it will be. Removing the old seal is the challenge in tight quarters without screwing up the housing. Don't think a seal puller can be used plus the shaft spline is protruding as well.

Thanks for all the replys!

John Schwab
PSC 34 #201
Norstar

 

[DaveMancini]

John,

The special wrench is part number 177099-09010. It's not cheap. Since I posted, I remembered that the O-ring was missing when the guy pulled the seal and he didn't see the purpose for it so he didn't put one back in. It looks like it's intended to keep fluid from migrating past the seal on the outside where it fits against the seal housing. I worried about his not having put it in, but I haven't have any leakage, but if you can get it in, all the better.

The seal came right out. It's not pressed in. The guy had a pick and a paint can opener for removal tools. He showed me how either one would have worked. The hard part is working in the space between the trans coupler and shaft coupler. Much depends on how far you can slide the shaft aft to make space. You will have to pretzel down so you can see to work or use a mirror (neither me nor my guy had to use one). Clean the shaft if there's any crud on it before sliding it aft to keep from tearing up the packing in the packing gland.

Use a pipe wrench on the trans coupler braced against the hull to hold the coupler so you can wrench on the nut. The nut is normal right hand thread (counter-clockwise to come off), unlike some boat transmissions.

The nut should be caulked after replacing it to keep it from loosening when in reverse. The caulking doesn't keep it from loosening when you get on it to remove it with the wrench, though. The dimple isn't that deep.

Forgive me if I'm telling you stuff you already know. Just trying to cover what I remember. Good luck. Let me know if you need anything else.

Dave

 

[DaveMancini]

John,

Hopefully, you can borrow the wrench. There is a webpage with a good picture of a wrench a guy made for the nut. It is obviously not as strong as the tool from Yanmar, which is really heavy duty, but it might work I suppose (I think the torque required is 60-80 lbs.). There are also some good pictures of the nut, etc.

Island Packet Photos (3JH2E Transmission Output Coupler - Album_ID 1596)

I would send you my wrench if I weren't in Mexico.

Dave

 

[Norstar]

Mission accomplished. Was able to replace rear seal without removing or lifting up rear of engine. Took me a bit longer than Dave's mechanic as I was hoping for a quick 2-3 beer job. Took me more like 6 hours and a 12 pack!!! Thanks Dave for the helpful information and part #'s.

John Schwab
PSC 34 # 201
Norstar

 

[desert rat]

Now another person who knows how to do this keep him on file so he can help others. Dn'to not expect me to help, I have done easy fobs like replacing universals at -20 degees farinheit in the snow and i won't do that again without threat of death.

 

[FMReady]

John,

Hopefully, you can borrow the wrench. There is a webpage with a good picture of a wrench a guy made for the nut. It is obviously not as strong as the tool from Yanmar, which is really heavy duty, but it might work I suppose (I think the torque required is 60-80 lbs.). There are also some good pictures of the nut, etc.

Island Packet Photos (3JH2E Transmission Output Coupler - Album_ID 1596)

I would send you my wrench if I weren't in Mexico.

Dave

Hi Dave - this is a much later response to this post but I found it in a search. My husband is trying to find the Yanmar Part you referred to (177099-09010). Would you consider letting him borrow it? I saw your offer in your post above. He's ready to head to a machinist but thought we might find someone on a sailing site who has one we could use. We would send it right back once the transmission nut that is consuming his life is removed. Thanks for considering - Tricia

 

[wsmurdoch]

I made a transmission nut tool from a 27mm deep impact socket that I bought from Harbor Freight that fits the nut at the rear of the transmission on my Yanmar 3HM35F. I made it with a hack saw, file, and a Dremel tool, but it would be much easier with a milling machine. I'd give it to you, but I am at home in Tennessee and the wrench is on the boat on the North Carolina coast. It will be a couple of weeks before I am there. Anyway, here are some pictures, and you can see what I did.

The horror story of our transmission and other problems starts with the March 26, 2019 entry in my wife's blog. Irish Eyes to the Bahamas

Bill Murdoch
1988 PSC 34
Irish Eyes

 

[FMReady]

I made a transmission nut tool from a 27mm deep impact socket that I bought from Harbor Freight that fits the nut at the rear of the transmission on my Yanmar 3HM35F. I made it with a hack saw, file, and a Dremel tool, but it would be much easier with a milling machine. I'd give it to you, but I am at home in Tennessee and the wrench is on the boat on the North Carolina coast. It will be a couple of weeks before I am there. Anyway, here are some pictures, and you can see what I did.

View attachment 138704
View attachment 138705

The horror story of our transmission and other problems starts with the March 26, 2019 entry in my wife's blog. Irish Eyes to the Bahamas

Bill Murdoch
1988 PSC 34
Irish Eyes

Thank you so much, Bill. This is a great idea. My husband's eyes lit up with hope. I didn't read the whole blog but it looks like your issue was that the nut fell off. Our trouble is getting the nut off. We'll try this solution, though. Hopefully, it will work! I love the pictures of the Bahamas. We were in Georgetown a few years ago. What a beautiful place.
Thanks again for the idea!
Tricia

 

[FMReady]

I made a transmission nut tool from a 27mm deep impact socket that I bought from Harbor Freight that fits the nut at the rear of the transmission on my Yanmar 3HM35F. I made it with a hack saw, file, and a Dremel tool, but it would be much easier with a milling machine. I'd give it to you, but I am at home in Tennessee and the wrench is on the boat on the North Carolina coast. It will be a couple of weeks before I am there. Anyway, here are some pictures, and you can see what I did.

View attachment 138704
View attachment 138705

The horror story of our transmission and other problems starts with the March 26, 2019 entry in my wife's blog. Irish Eyes to the Bahamas

Bill Murdoch
1988 PSC 34
Irish Eyes

Hi again - my husband bought some pieces to copy what you've done above but he's wondering if you would mind lending us your tool? We know it may be a few weeks before you get out to your boat, and then some time in transport. But he's thinking it may take him that much time before he's able to make a new one anyway. We would cover all shipping and send it back to you without delay. If that is ok, please send me a private message (conversation?) and I'll can arrange shipping details with you. Appreciate you considering it!

Thanks,
Tricia

 

[wsmurdoch]

I'm happy to send you the wrench. I sent you a message.

Bill

 

[nateinmaine]

Bill, that tool you fashioned is a work of art! Really eloquent solution. Thanks for the post and the inspiration. Nate