How easy is it to replace a leaky gasket on my Hurth transmission?

[Bene505]

Can I do this myself?

I spent Saturday removing our Hurth 360? transmission from the boat. It was slowly dripping transmission fluid into the engine bilge and making quite a mess.

I'm planing to wipe it clean, put some fluid into it and seeing where the fluid comes out. I'm thinking it's the gasket where the prop shaft attaches.

Does anyone know if it's possible for a reasonably mechanically inclided person to do this himself? I don't want to pay for a rebuilt transmission when this one otherwise works fine.

(I have some nice pictures of the removal that are still in the camera.)

Regards,
Brad

[kd3pc]

Originally Posted by Bene505

Can I do this myself?

I spent Saturday removing our Hurth 360? transmission from the boat. It was slowly dripping transmission fluid into the engine bilge and making quite a mess.

I'm planing to wipe it clean, put some fluid into it and seeing where the fluid comes out. I'm thinking it's the gasket where the prop shaft attaches.

Does anyone know if it's possible for a reasonably mechanically inclided person to do this himself? I don't want to pay for a rebuilt transmission when this one otherwise works fine.

(I have some nice pictures of the removal that are still in the camera.)

Regards,
Brad

if it is the prop shaft....then you are really lucky as that is a seal...and you should be able to easily replace it, once the shaft coupler is removed...

some of the gaskets will require the cases to be split and that is a horse of another color...

all the best

[Rockter]

Bene...

If you take a picture of the place where the fluid is leaking, I reckon we could come up with some ideas.

Changing a seal is not likely to be difficult, if only we could see a picture of it. Seals are not too expensive either, if you source them from the web.

It is probably a lip seal on the tailshaft that has failed, and in my experience with Volvo gearboxes, it is not too difficult to fix.

Watch when you take the gearbox off the engine. Sometimes there are ultra-thin spacer shims in there, and they can fall in the bilge. I had that happen once, and it is an utter heart-stopper. It is also easy to damage them, they are so thin.
.

[jrd22]

If it was mine and I had it out I would re-build it which would probably only entail seals, bearings and gaskets if it was operating properly when taken out. Chances are that the seal leaking might be an indication that the bearings need replacement or the shaft is worn or damaged in the seal area. Have you talked to a shop about cost to rebuild it for you if you don't feel qualified?

[HUGOSALT]

jrd22 makes sense...looking into changing seals/bearings.

Anyone familiar with boatdiesel.com? Have thought about
joining ($25. membership fee annually) Could be helpful
in this case. Brad might be worth your while to check out.

[Bene505]

More background until I can test where the fluid is coming out...

A "mechanic" at a marina knew that the dipstick was missing from the transmission -- you know, the dipstick with the pressure vent hole in it. So he inserted a plastic cork into it. He used the type of cork that has a lever to lock it down tight.

I found the dipstick and replaced it, but the damage was done. I believe this is the cause of the drip, that is blew-out a seal or gasket.

Otherwise the transmission works fine.

Regards,
Brad

[Rockter]

Bene...

The gearbox really has to have a vent on it somewhere, otherwise it will be pressurised as it heats. The sealing of the vent hole may well have caused the problem.

[Bene505]

Originally Posted by Rockter

Bene...

The gearbox really has to have a vent on it somewhere, otherwise it will be pressurised as it heats. The sealing of the vent hole may well have caused the problem.

Yes, that's what I was thinking.

Regards,
Brad

[Maine Sail]

Bene,

Some of these gear boxes require special tools to press parts on and off the output shaft, mine does, and these tools are expensive and often specific to the model gear box. My output shaft also needed a light machining where the seal rides as rust had crept in and ruined the seal and surface. I let Hansen Marine replace my output shaft seal. If it is a case leak or shifter seal that's easy but an input or output seal can be another can of worms on some gear boxes..

They are not difficult to re-build but often require an understanding of how they work. There are MANY parts in there that are easy to mix up the placement of when re-assembling and sometimes even rotating a part 180, that looks the same either way, can cause bad things to happen.

[Bene505]

Originally Posted by Maine Sail

Bene,

Some of these gear boxes require special tools to press parts on and off the output shaft, mine does, and these tools are expensive and often specific to the model gear box. My output shaft also needed a light machining where the seal rides as rust had crept in and ruined the seal and surface. I let Hansen Marine replace my output shaft seal. If it is a case leak or shifter seal that's easy but an input or output seal can be another can of worms on some gear boxes..

They are not difficult to re-build but often require an understanding of how they work. There are MANY parts in there that are easy to mix up the placement of when re-assembling and sometimes even rotating a part 180, that looks the same either way, can cause bad things to happen.

Maine,

Looks like I may have lucked out.

Reposting from the A-S forum:

After taking the transmission out, I setup a little test to see where the fluid was leaking out. It turns out that the leak is where the 2 pieces of the tranny come together.

Here is where the leak is, on the bottom of the transmission. (The tranny is on its side in the picture.)


It's not here where the spinning part is.


Next I plan to take the two sides apart and put a new gasket in. If anyone knows a good place to get a gasket for a Hurth transmission, please let me know. I guess I'll try Hurth, but I'm wondering if this is one of those cases where you can make your own out of a piece of gasket material.

Regards,
Brad