MS2B stiff gear disengagement - eccentric wear.

smb

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Bit of history.
Our gearshift has always been notchy but acceptable, however I guess it was getting progressively worse but unnoticed as I adapted to it . After launch last spring, with my expectations reset, it concerned me how bad it was and after some checks decided the oil cooler might be leaking water into the oil and after some discussion on this forum I disconnected it. Three oil flushes later and no improvement.

Long story short.
Process of elimination determined the cable and morse were not guilty.
Tried several times to set the dog limit screw as per the workshop manual but could not achieve shaft 'binding' as required.
Bit the bullet and removed the box, and found the end of the dog is deeper in the box than the length of the limit screw without shims.
Gearshift works somoothly enough when no rotation on input or output.
Observed that the dog was working in and out as ouput shaft rotated.
Drained the oil, black as your hat after c100 hours.
Removed the input shaft/gear and this is what I found.

https://www.dropbox.com/s/eyghhheyv6rnjdp/IMG_1153.MOV?dl=0

As can be seen the V groove that the dog runs in has worn eccentrically, both in terms of the depth of the V and the sides. Uniform wear I could understand especially if the oil has been contaminated, but this wear pattern does not make sense.

I have since removed the sleeve. As far as I can prove turning the shaft by hand and a rule held agains the casing the shaft runs true in its bearings with no noticeable slack, and the 'non-working' parts of the sleeve also run true. The sleeve also runs up and down its helix smoothly and engages solidly with the gears.

Any suggestions what could of caused this and what to do next would be welcome.

Steve
 

smb

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Thanks. Is the sliding sleeve a wear item? Assuming its the original box it's done about 4500hrs, including 2 transits of France which probably had eneough gearshifts for a lifetime.

Not sure machining the V is an option as the material might have worn to far already.


Steve
 

pvb

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Thanks. Is the sliding sleeve a wear item?

No idea how long it's supposed to last, but it's a VP spare part at around £500.

As for machining the sliding sleeve, it might be worth asking a VP workshop. As far as I recall, the sliding sleeve doesn't need to be firmly held in place by the dog, merely moved into the drive position, when the spiral thread then forces it into the clutch drive position. So it might work with a slightly wider V-groove. I wonder why it has worn unevenly?

Do you have the workshop manual? I have a PDF of it.
 

smb

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Just found this https://www.youtube.com/watch?v=D8nkoGnmLU8 from a thread on cruiser forum.

This is I believe a new sleeve and again the dog can be seen moving around a lot. Maybe thats a red herring and brings me back to the original question, why is it hard to disengage and is the black oil a worry?

Happy (ish) to spend the money on parts but would like to be confident I've a fair chance of success.

I have the manual thanks.
 

VicS

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Just found this https://www.youtube.com/watch?v=D8nkoGnmLU8 from a thread on cruiser forum.

This is I believe a new sleeve and again the dog can be seen moving around a lot. Maybe thats a red herring and brings me back to the original question, why is it hard to disengage and is the black oil a worry?

Happy (ish) to spend the money on parts but would like to be confident I've a fair chance of success.

I have the manual thanks.


The oil should certainly not be going black Oil drained at the normal recommended service intervals should still be "clear and bright" in appearance and no more than slightly darker in colour than when new.

Assuming the oil is not burnt I'd suspect corrosion due to sea water contamination.

You are using engine oil ?

You do put the gear box in reverse while sailing ?
 

smb

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The oil should certainly not be going black Oil drained at the normal recommended service intervals should still be "clear and bright" in appearance and no more than slightly darker in colour than when new.

Assuming the oil is not burnt I'd suspect corrosion due to sea water contamination.

You are using engine oil ?

You do put the gear box in reverse while sailing ?

Yes to both. No corrosion visible. Contamination perhaps from either water ingress or erosion/wear of the parts. Oil does not smell burnt and on closer inspection is more a grey/Black with a film/smear in it.

I think it’s wear in the interface between dog and sleeve. Watching the selector with the top cover and gear removed and the input being spun with a brace, on occasion the dog is forced outward rather the sleeve moving.

Think I’ll try some replacement parts and keep fingers crossed.

Steve
 
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