M25 transmission mystery?

B

byeager

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Jul 15, 2020
8
O'Day 34 Rock Hall, Maryland
I have a 2004 O'Day 34 with an M25. Last time out at higher RPMs, there was a whining followed by a loss in power. I took her out of gear, lowered the RPMs and reengaged. It happened one more time then ran fine at lower RPMs to get back to the slip.

I went to check the transmission fluid and the dipstick is not on the bolt where it should be. Could the issue I experienced be the missing dipstick or something else?

Any thoughts would be appreciated. Thank you.
 
dmax

dmax

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Jul 29, 2018
1,224
Telstar 28 Buzzards Bay
The dipstick is not necessary for the transmission to operate but the right amount of fluid is. Is there a hole where the dipstick should be or is there a bolt with no dipstick? What you describe could be caused by low fluid level. I'm assuming you have a 1984 vs. 2004 :)
 
B

byeager

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Jul 15, 2020
8
O'Day 34 Rock Hall, Maryland
Thank you, and you're right - 1984:)!

There is a bolt with no dipstick. The previous owner said it was there so it must have fallen off in the last year. If it fell into the transmission, that would niot cause an issue? I was afraid it may have torn things up inside.

I had a hunch that the fluid might be low so that's what made me check. Any idea how to check it without the stick? I guess I can buy another.
 
jviss

jviss

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Feb 5, 2004
7,089
Tartan 3800 20 Westport, MA
byeager said:
Thank you, and you're right - 1984:)!

There is a bolt with no dipstick. The previous owner said it was there so it must have fallen off in the last year. If it fell into the transmission, that would niot cause an issue? I was afraid it may have torn things up inside.

I had a hunch that the fluid might be low so that's what made me check. Any idea how to check it without the stick? I guess I can buy another.
Click to expand
Are you sure the bolt you removed is the dipstick? Any pics?
 
dmax

dmax

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Jul 29, 2018
1,224
Telstar 28 Buzzards Bay
"Any idea how to check it without the stick? I guess I can buy another." - you could try borrowing one to measure it, there are a lot of those Hurth transmissions out there. Assuming its the dipstick bolt (as jviss points out) and it broke off inside, you definitely want to fish it out of there.
 
B

byeager

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Jul 15, 2020
8
O'Day 34 Rock Hall, Maryland
Great question, but I am 99% sure I have the right bolt. I didn't take any pics, but it looks right per YouTube and the label on the transmission itself. There are no other places a dipstick could be.

I will fish out the dipstick first then check the level before doing anything else. Here's to hoping the issue is just the fluid!

Thank you both very much!
 
B

byeager

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Jul 15, 2020
8
O'Day 34 Rock Hall, Maryland
Update - Mechanic said dipstick is in there under the gears. He's never seen one fall into the trans before.

He found a few small pieces of metal with an extension magnet and said it's the dipstick and possible pieces of the gears. Recommends new transmission.

I wanted to get a reality check on this diagnosis. It operated fine at lower RPMs, and the noise I heard did not sound like grinding metal.

I added a little bit of fluid and cleaned a lot of barnacles from the prop and shaft.

I know I am grasping at straws here. Is there any hope the symptoms were NOT caused by the dipstick falling into the transmission?

Thanks.
 
dmax

dmax

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Jul 29, 2018
1,224
Telstar 28 Buzzards Bay
I would do as little disassembly as possible to remove all the metal - if it's gear metal, that's not good. If it's just the dispstick chewed up then change the fluid, get a new dispstick and give it a go. I imagine the gears are made of stronger metal than the dipstick.
 
jviss

jviss

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Feb 5, 2004
7,089
Tartan 3800 20 Westport, MA
Unfortunately, on the M25 it's not so easy to remove the transmission to do anything to it, as it's bolted to the bell housing from the inside, and the rear engine mounts are bolted to the bell housing.

That said, there are a million moving parts in these transmissions, and if it whines or slips it could be the clutches, not necessarily gears. They are rebuildable, though.
 
dmax

dmax

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Jul 29, 2018
1,224
Telstar 28 Buzzards Bay
If you need to go with a new transmission, read this thread, there's a reasonably priced alternative:

Transmission slippage on a Catalina 28 mark 11?

I own a 2004 Catalina 28 mark 11 second year of ownership. This year I've experience , what I believe to be forward gear "slippage" I have a M 25XPB with a Hurth ZF 5 M transmission. When I back out of my slip and then go forward , any throttle other than idle speed seems to disengage forward. I...
forums.sailboatowners.com
 
B

byeager

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Jul 15, 2020
8
O'Day 34 Rock Hall, Maryland
That sounds like a good plan!

Apparently, the stick is at the bottom under the gears. I can't really open it up but can fish around more with the magnet, get what I can, and change the fluid. I just don't want to damage anything in the engine, but it sounds like that's not a concern.
 
B

byeager

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Jul 15, 2020
8
O'Day 34 Rock Hall, Maryland
Yes, he said he'd have to move the whole engine to replace the transmission on this one.

And from the previous article dmax linked, it could very well be the clutches.

Well, I still may end up with a new transmission, but I'll give the other solution a try.

As long as I won't be doing any other damage (transfer case, etc.) by trying it.

Thank you both! I'll let you know how it goes.
 
B

byeager

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Jul 15, 2020
8
O'Day 34 Rock Hall, Maryland
Wow - that PRM 60 looks to be half the price of the quote I got on another one, even after converting to US dollars:).
 
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