Stupid Transmission

Jan 22, 2008
597
Oday 35 and Mariner 2+2 Alexandria, VA
I got underway yesterday for Annapolis. Only an hour after leaving the dock (in no wind) we heard a rhythmic scratching and thunking sound. It truly sounded like I snagged a fishing line and the lure was banging around. The sound vanished after about 15 seconds. We checked the engine compartment, ran the throttle up and down and noticed no change in performance. About a half hour later, it did the same thing, this time, the thunk sounded metallic. I crawled back along the engine and noticed the prop shaft turning slower and slower. Shifting gears and the prop no longer turned with the engine in any gear. So we somehow drift sailed, and got into Fort Washington to tie up and weigh options. No diesel mechanics are available in the area for at least ten days. After slowly swinging the boat by lines out of the slip we used the 2 hp dinghy outboard clamped to the ladder to get back into the river, then slowly worked our way back to our home slip, 6 miles up the river. Add in one squall and finally, 10 hours after leaving home, we are back.

Now to the issue at hand. What the heck happened? My thoughts are that the damper plate failed and the engine is no longer turning the transmission. Is this a job that I can tackle? Or is it time to make the payments on a diesel mechanic's boat/house/rv?
 
Sep 15, 2009
6,243
S2 9.2a Fairhope Al
sorry to hear this D.....all this time i thought you were a mechanic......what kind of engine and tranny do you have....do you have room to pull it out without pulling the engine...
 
Sep 25, 2008
7,435
Alden 50 Sarasota, Florida
My experience with damper plate woes leads me to believe your description is not a typical damper plate failure. However, this is one of those things which are impossible to diagnose via internet.

Parenthetically, you might want to add tow insurance to your boat liability policy. For around $30/year, it would have been a less stressful return home.
 
Feb 26, 2004
23,047
Catalina 34 224 Maple Bay, BC, Canada
Dan, the C36 group used to have a great section discussion on their forum about damper plates, but they inexplicably just locked down their entire website to non-C36IA members, including their forum. Try looking up damper plate issues on the C350 website. I've heard they have some good stuff there. Do a Google search. Good luck.
 
Jan 22, 2008
597
Oday 35 and Mariner 2+2 Alexandria, VA
Thanks all. I do have towing insurance, but I guess I was hoping the winds would pick up a bit. My marina manager met me at the channel and gave me a tow into my slip.

Yeah Woody, with all the work I have done lately I feel like a diesel mechanic. I have rebuilt two diesels, but never played with transmissions (yet.) I have an associate who is my "on call" mechanic and he is thinking to start with the damper plate since there was no power sent to the transmission, and no change in loading in forward or reverse. If the problem is the transmission itself I will still need a new damper plate. I found a matching plate at Torresen for $211 delivered.

Incidentally, my engine is the M-25 with a hurth HBW50 transmission. Pretty easy to access, just need to jack the aft end of the engine to remove the bell casing and transmission all at once. I am going to give it a go tomorrow morning and see what happens.
 
Sep 29, 2008
1,944
Catalina 310 #185 Quantico
Transmissions and Damper Plates

Dave, If you go over onto the Catalina 310 forum we have all had fun with our transmissions and damper plates. From the sound of it you have a transmission problem. IMHO, I would start by pulling the transmission, then you can immediately check out the damper plate and then see about getting the transmission checked out. Our 310's have the M25XPB engines which are similar to yours. But in the process of pulling your transmission you will be able to check out the splines on the transmission shaft as well as inspect the damper plate. Here is one of the threads - http://forums.catalina.sailboatowners.com/showthread.php?t=157853

One question would be is which damper plate do you have? If it is one of the OEM ones with the plastic ribbons they had a high failure rate, but are smoother. I went with a Sachs Sachs Damper Plate #10 1866 061 001 that has worked out fine. I got it from a marine supply place up in Seattle called MER Equipment (http://www.merequipment.com/pdfs/Dri...chure-5-22.pdf).

I pulled my transmission off without having to jack the engine up when I was replacing my damper plate. Putting the transmission back on required me to jack the engine up as with a new one the splines were all there and there was not enough slop to just slide it in on a slight angle. :D You do not need to pull the bell housing as you can just reach in (you will probably need to rotate the engine as you go as you will only be able to access the bolt on top). If you need to replace the damper plate it will fit out the back of the bell housing.
 

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Jan 22, 2008
597
Oday 35 and Mariner 2+2 Alexandria, VA
Damper plate?? What damper plate??



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Had to lift the engine since there is no adapter plate like on the later m25x series. Total time was three hours including lunch and beer(s). Waiting on the new part. If it is nylon based, I will send it back for a more solid model. In the meantime, I will flush the heat exchanger and flush the antifreeze...since it all dumped into the bilge, missing my bucket.
 
Jan 22, 2008
597
Oday 35 and Mariner 2+2 Alexandria, VA
Just hand spun the tranny. Works like normal. I am going to take it home to clean the bell housing and give the transmission a good flush and fill.
 
Sep 15, 2009
6,243
S2 9.2a Fairhope Al
Damper plate?? What damper plate??



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Had to lift the engine since there is no adapter plate like on the later m25x series. Total time was three hours including lunch and beer(s). Waiting on the new part. If it is nylon based, I will send it back for a more solid model. In the meantime, I will flush the heat exchanger and flush the antifreeze...since it all dumped into the bilge, missing my bucket.
well Dan it looks to me like you are a mechanic you nailed the problem straight away...now you can sleep better tonight ....i know how theses things nag at ya till you find out whats what you will be sailing wednesday or thursday at this rate
 
Jan 22, 2008
597
Oday 35 and Mariner 2+2 Alexandria, VA
Thanks! Come on UPS, and deliver!

On the older M25 engines, the transmission connects from inside the bell housing. The M25XP, and XPB have an adapter plate that allows the transmission to be removed without the bell housing being removed. Unfortunately for me, this was not the case. I had to pull the heat exchanger, the linkage, grounding connection, exhaust riser, back off the prop shaft, then lift the rear of the engine. All in all, not too bad a job. Here's hoping the install goes as smoothly.
 
Jan 22, 2008
597
Oday 35 and Mariner 2+2 Alexandria, VA
DONE! Replacement part from TOAD Marine Supply (Torreson) arrived on Friday, the "OEM version" and not the Universal version is actually the Sachs model damper plate. A quick trip to the the hardware store for new bolts, and this evening, I put it all back together.

The whole process was...
Breakdown:
1. Disconnect transmission linkage, muffler hose, raw water hoses.
2. Drain all antifreeze.
3. Remove all fresh water hoses from heat exchanger, and remove heat exchanger.
4. Disconnect prop shaft from transmission.
5. Remove grounding wire from bell housing.
6. Attach lift strap, loosen front mounts, remove retaining bolt from rear mounts.
7. Tension lift. Lift rear of engine (watch exhaust manifold to ensure it cleanly releases from muffler.
8. Remove bottom bolts from bell housing.
9. Brace bottom of bell housing with 2x4 and then remove all but top center bolt.
10. Lift bell housing slightly and remove final bolt. Lower bell housing and remove from compartment.
11. Remove flywheel adapter plate from flywheel, clean shrapnel from bottom of casing.
12. Remove what was left of damper plate from flywheel adapter and bell housing.
13. Drain and fill transmission fluid.
14. Flush and inspect heat exchanger.

Installation:
1. Attach damper plate to flywheel adapter.
2. Bolt flywheel adapter to flywheel.
3. Align splines and damper plate and re-install bell housing.
3. Top, bottom, left, right, bolts installed, turn motor through to verify transmission engagement.
4. Torque all bell housing bolts.
5. Lower engine onto stern mounts, re-attach exhaust hose to muffler.
6. Re-install heat exchanger, connect all hoses.
7. Re-connect ground wire to engine bell housing. Connect transmission linkage.
8. Align prop shaft to output shaft. Torque all engine mount bolts.
9. Refill antifreeze, burp system (low power run).
10. High power run up, forward, neutral and reverse.
11. Top up antifreeze.
12. Run in forward for 30 minutes at medium load. Check/re-torque all fasteners. Adjust transmission linkage if required.

Am I missing anything that I will regret when I take it out for shakedown later this week?
 
Jan 22, 2008
597
Oday 35 and Mariner 2+2 Alexandria, VA
I replaced the cutless two seasons ago. And it was inspected on haul out last month.
 
Oct 17, 2011
2,809
Ericson 29 Southport..
Looks like a splash to me. Did the engine line up fairly close to where it used to be? Maybe a little tweak after it has settled, but otherwise I don't see anything amiss.
 
Jan 22, 2008
597
Oday 35 and Mariner 2+2 Alexandria, VA
I should have added this was all done in water. The alignment was just barely off, took about two turns up on the port front mount and the fittings meshed perfectly. The .001 feeler gauge will not slide between the facing plates.