Twin Disc MG 360 Corrosion problem

[bwindrope]

I replaced my original Hurth transmission with a Twin Disc MG 360 a few years back, in 2013, and have enjoyed the smooth operation ever since. However, about a year ago I discovered a very distressing thing. The shift arm itself has become badly and fully corroded with rust! I checked it one day, and was stunned to see this. This is a marine transmission, after all!

I had never had one spec of rust or corrosion on my Hurth transmission after nearly 30 years in the same environment.

So I quickly sprayed it with some ACF 50, regretting not having done that from the start, and have been watching it ever since. I reached out to the place where I bought it, Mill Log Marine in Kent, WA a local Twin Disc dealer, thinking to see if they had had a recall, or any program of replacing the shift arm with new.

I'm sorry to say that the response from Mill Log was silence, and then a terse statement saying that even if you could find a replacement shift arm, they would be $67 and the same material. What the heck?

Here is a picture of the corroded shift arm:
Stories of Aeolus- Our Gulf 32 Pilothouse: Corroded Shift Arm on MG 360-No help from Mill Log or Twin Disc

The tranny works great, but who wants to install a tranny only to have to pull it soon after to deal with corrosion? I'm going to pull my engine for some cleaning and love this summer anyway, and will pull off this arm to see what is left and to paint it. Bummer.

[a64pilot]

I'd at least clean it in place with a wire brush, then treat it with rust killer of your choice, then paint it

[Sailmonkey]

I've got the same gear, and have been spraying the whole thing annually with boeshield. I know that doesn't help now, but fwiw

[bwindrope]

Yes, dealing with the corrosion problem is not so much the issue, though it is a shame to have to do it at all. My main gripe is that Twin Disc would make a marine transmission with such highly corrosive metals. And that Mill Log locally treats this as a non-issue.

Like I said I am hauling in a few months anyway, and while out, will be pulling up my inboard to give it a thorough cleaning and evaluation. This will allow me easy access to remove this shift lever and do the cleaning and painting necessary to make this less of an issue for a few years. You can see in the picture that it is not just the shift arm, but the surrounding housing, so it would be practically impossible to do a good job on this with the tranny and engine installed.

This is almost a public service announcement that anyone seeking to purchase one of the sailboat marine trannies from Twin Disc should proactively remove and paint the shift arm and surrounding housing.

[jimbunyard]

So let's get this right...you installed, or had installed, a replacement transmission, with (what should have been) obviously unprotected cast or forged iron fittings in, or close to, the bilge in a saltwater environment, exposed to large temperature swings (and thus heavy condensation) and expect the dealer or distributor for Twin Disc to take responsibility for a little surface rust?



Pardon me, but I'm a big believer in holding corporate interests responsible for their products, actions, and consequences from use of those products, even more responsible than individuals, but I'm also leery and equally distressed at people directing misplaced blame on others, be they corporate or individual.

You, or your installer, should have treated/painted/rustproofed the gear before installation...I'd have (and regularly do) replace exposed carbon steel nuts, bolts and washers with stainless ones, (if they have the required strength in the application) to cut down on at least that aspect of maintenance, and also paint brand new equipment if their finish appears below par for the application...

When you signed the check for the box, you agreed that it was fit for purpose...

[bwindrope]

Originally Posted by jimbunyard

So let's get this right...you installed, or had installed, a replacement transmission, with (what should have been) obviously unprotected cast or forged iron fittings in, or close to, the bilge in a saltwater environment, exposed to large temperature swings (and thus heavy condensation) and expect the dealer or distributor for Twin Disc to take responsibility for a little surface rust?



Pardon me, but I'm a big believer in holding corporate interests responsible for their products, actions, and consequences from use of those products, even more responsible than individuals, but I'm also leery and equally distressed at people directing misplaced blame on others, be they corporate or individual.

You, or your installer, should have treated/painted/rustproofed the gear before installation...I'd have (and regularly do) replace exposed carbon steel nuts, bolts and washers with stainless ones, (if they have the required strength in the application) to cut down on at least that aspect of maintenance, and also paint brand new equipment if their finish appears below par for the application...

When you signed the check for the box, you agreed that it was fit for purpose...

Well Jimbunyard, I suppose we disagree in strong terms. Having thoroughly refit my boat from stem to stern, I have dealt with all possible types of marine equipment. To say that it is essentially buyer beware with an expensive marine transmission is, to me, ridiculous. That is like saying when we buy a new car we should expect the brakes to fail and the transmission to fall out if we hadn't personally verified their proper manufacture and construction.

Make no mistake, all of us DIY people have to deal with ongoing issues of corrosion and such, and that is just chemistry and physics for the most part. But to say a marine transmission should not come with stainless steel or other high grade metal components, as clearly my Hurth transmission did, is to disavow the responsibility of the manufacturer and misplace it on the consumer.

If I purchase a windlass, I have the reasonable expectation that the manufacturer has created a machine that is designed for the marine environment. This is the case with my beautiful Lofrans Tigres. If I purchase all manner of blocks, I should expect they are made for the marine environment. They are. And If I drop a cool grand or two on new winches, I should expect to have to grease them, but not to worry they will rust out before my eyes. They do not.

So while I agree we have responsibility as boat owners to maintain all sorts of things, it is the responsibility of manufacturers to design and construct products made from appropriate materials for their intended use.

[jimbunyard]

Originally Posted by bwindrope

Well Jimbunyard, .....
So while I agree we have responsibility as boat owners to maintain all sorts of things, it is the responsibility of manufacturers to design and construct products made from appropriate materials for their intended use.

"and have enjoyed the smooth operation ever since."

Which, by your own admission, they did. Caveat emptor. Did you, by any chance, think that, maybe, the choice of a (probably) forged cast iron shift arm has a longer duty cycle than either an aluminum or bronze or stainless steel one (surface rust notwithstanding)?

TD has been in business for almost a hundred years, has a pretty high reputation in their field, and apparently know what they're doing. By all means, when you trash your boat because the shift arm provided by TD fails, sue to your hearts' content. Meanwhile, when a TD dealer or distributor ignores you for bothering them with trifling complaints, I'll offer up a sad sigh to the god of retail tolerance for beleaguered partsmen....

Meanwhile, if you want to see an actual instance of manufacturer culpability, have a look at http://www.cruisersforum.com/forums/...an-179410.html

[bwindrope]

Originally Posted by jimbunyard

"and have enjoyed the smooth operation ever since."

TD has been in business for almost a hundred years, has a pretty high reputation in their field, and apparently know what they're doing. By all means, when you trash your boat because the shift arm provided by TD fails, sue to your hearts' content. Meanwhile, when a TD dealer or distributor ignores you for bothering them with trifling complaints, I'll offer up a sad sigh to the god of retail tolerance for beleaguered partsmen....

We are urged these days to engage more with people who see things differently than we do and this is a philosophically interesting exchange to me. You sound pretty edgy about something that for all we know does not affect you personally or your pocketbook.

As to your contention that because Twin Disc has been around and has a good reputation, I find that argument weak. Let me use GM as an example. GM has been in business since 1908. Built a lot of cars. People still buy their cars. When someone buys their cars there is a reasonable expectation that the darn thing will work for the specified purpose. However, GM, like all car manufacturers, has a history of recalls. A history of so many recalls in fact that they have a whole web page devoted to it: https://my.gm.com/recalls

GM recalled some 24.6 MILLION cars in the US in 2014. We are all aware of the fatalities and lawsuits related to some of these recalls. Faulty designs. Faulty manufacturing.

So to claim that because a company has been around a long time, and makes some good products, somehow relieves them of all culpability is an absurd argument.

Marine Transmissions may not required Federal oversight and official recalls, but sailors like us should be able to expect the marine industry to provide us with products engineered to succeed in the applications they are meant for. In this case, Twin Disc did not. Oh, and as for material strength!!! Did you not read that the shift arm on my old Hurth never had a spot of rust?

[chris95040]

I think Jim's point is that despite your displeasure with how the shift lever looks it hasn't impacted it's operation in any what whatsoever.

Comparing it to transmissions falling out of a car or a windlass rusting away is disingenuous. There's likely enough material for that shift lever to keep working fine for the next 50 years, so this is simply a cosmetic issue on a rarely seen piece of gear.

If that's wrong, and that shift lever stops working before it's time (or looks like it's going that way) then you've got a point.

[bwindrope]

I appreciate the clarification and I agree that if the corrosion is only superficial then it may a moot point.

Yet I stand by my concern that it shouldn't be made of corrosive material at all. It has corroded aggressively, which weakens my faith that it may be, and remain, superficial.

And my points of comparison to other items wasn't to equate the severity of the problems they can present (though with some consideration a failed tranny shifter can put one in worse conditions than a car transmission or windlass problem. I shudder to think of some occasions I've had in the Straits of Juan de Fuca or Georgia Strait when my functioning engine and transmission saved my family from serious calamity), but to equate the manufacturer responsibility for good design, which they share.

In any case, when I pull it off and clean the tranny and treat the rust and paint it, I will then be good. If I learn anything from that of interest, I will report it here. And now others know they should do the same treatments on this area before they install a MG 360 or MG 340.