CD 25d transmission slipping

[abcnuzeman]

Im having intermittent slippage when motoring, occasionally only able to make 1 or 2 kts. regardless of throttle. At some point, the slippage seems to stop and speed increases and it appears by looking at the wake that the prop is spinning faster...more turbulence, etc. I'm mechanically inept but the fluid is fine, the shift lever seems to be engaging properly and the shaft spinning properly. Am I overlooking an obvious problem or do I have to bite the bullet and try to pull the transmission and find someone to check it out for me. Also, probably a foolish question, but I haven't checked the stuffing box or replaced the filling. Could this be having some effect? Any ideas?

[Steve Laume]

I had some slippage in Raven's Hurth transmission many years ago. I talked to a factory rep at the Mystic Boat Show and he suggested I change the fluid and it would probably get me through the season. I then pulled the engine and took the transmission off so I could have it rebuilt. I ordered the clutch plates and considered doing it myself but then thought better of it. I took it to a small, local transmission shop and the guy said he could do it. It saved me a bunch of time and money and it came out fine. I'm not sure how many guys would take this on but it worked out great for me.

Plan on doing something because it is going to get better or fix itself.

On the Universal engine, the transmission was bolted to the bell housing from the inside. This meant that the bell housing had to come off and that is also where the engine mounts attached so the engine had to come out to get the bell housing off in order to take off the transmission. I would love to know who engineered that mess.

Best of luck, Steve.

[Frenchy]

The only other advice I might offer is to make sure the transmission is not overfilled. That can result in
slipping. Also, be absolutely sure the shift lever is fully engaging. You can disconnect the transmission
after shifting to forward and see if you can manually move the lever farther forward.
If none of this helps, then it's time for professional help. Good luck - Jean

[abcnuzeman]

Thanks for replies. Sorta confirms my worst fears. Something's wrong. I can't fix it. It's gonna have to be done on the hard. I need to find a marine transmission guy. It's gonna be expensive. Sigh.

[Paul D.]

Do this test. If it is a Hurth HW 50 or 100 it is likely linkage.

• - Make sure the fluid level is correct as described above
  - Shift regularly and see how it does, i.e. if there is any delay from time of shift to transmission engaging
  - Remove shift cable at transmission
  - Shift with the lever on transmission housing using full range

If it works that way without delay you'll need to adjust the shift cable so it is using the full range of the shift lever on the housing.

Good luck. I have heard these have a ten year lifespan, but we must not invite fate....