Hurth HBW10 transmission won't go into forward

[theglo]

We just arrived into Nassau a few days ago and my transmission has decided to have an issue. The boat is new to me but the transmission was supposedly replaced with a rebuilt one only 6 years ago, a few hundred hours tops.

First, it was intermittent. I'd shift into forward and it would not go forward, then it would catch and be fine.

Then, it was much less intermittent and more or less non-existent in forward.

When I shift into forward it DOES turn the prop shaft, however, it does not add more power when I rev up the engine. It is so light I can grab the prop shaft and stop it with my hand.

I'm assuming the clutch pad (or whatever its called) that engages the forward gear is muffed up.

The only other symptom is the audible clunk when shifting gears is evident when shifting into reverse (reverse works fine) but is non-existent when going into forward with the engine on. With the engine off I can feel the clutch engage when I shift into forward but it is less "clunky" than reverse.

Was supposed to be headed to the Exumas tomorrow AM. Likely not happening but am hoping for a last minute Hail Mary solution I may not be thinking of.

I also checked the prop. Nothing going on there.

Attached is a video I just took of what's happening.

ALSO, I measured the travel of the shifting lever and it appears to be within tolerance according to the manual.

ALSO, I changed the transmission fluid. And I added some Lucas stop slip transmission goo.

THANKS ALL: FOR YOUR HELP!

https://www.youtube.com/watch?v=GiWVP7Xo0FM

[Sailmonkey]

Unfortunately the gear is going to need to be opened.

For a short term solution you may be able to shim the ahead clutch pack, but for a long term you’ll need to replaces the clutch discs.

Now the real pain. If you cannot do this yourself, it’s almost not viable to pay for the parts, shipping and labor to repair the gear. In other words buy a new transmission.

[theglo]

Originally Posted by Sailmonkey

Unfortunately the gear is going to need to be opened.

For a short term solution you may be able to shim the ahead clutch pack, but for a long term you’ll need to replaces the clutch discs.

Now the real pain. If you cannot do this yourself, it’s almost not viable to pay for the parts, shipping and labor to repair the gear. In other words buy a new transmission.

Figured. Can you elaborate on your "shim the ahead clutch patch" idea?

[Sailmonkey]

It may be possible to add some shims to the shaft thrust washer to keep the clutch discs closer together, but once you’re that far into the gear you may as well just replace the discs. I’d probably only attempt this if you were in The middle of nowhere.

[theglo]

Originally Posted by Sailmonkey

It may be possible to add some shims to the shaft thrust washer to keep the clutch discs closer together, but once you’re that far into the gear you may as well just replace the discs. I’d probably only attempt this if you were in The middle of nowhere.

Yep, wasn't planning on being in the middle of nowhere until tomorrow so I suppose in the grand scheme of things all is well.

[wsmurdoch]

Our KBW10 (the Yanmar version) failed in Morgan's Bluff in 2019. We sailed the boat into a slip at Palm Cay and had the transmission repaired by Marine Diesel Ltd in Nassau. The repair did not hold and the transmission failed again later in the trip, but with the help of Marine Diesel Ltd we made temporary repairs and continued on with our trip. On our return to North Carolina I ordered parts to fix the transmission myself, but with the strong advice of a nearby retired long term Yanmar mechanic, I sent the transmission to East Coast Marine Transmission in NJ for a rebuild. We have had no further problems.
https://irish-eyes-to-the-bahamas.blogspot.com/2019/03/
https://irish-eyes-to-the-bahamas.blogspot.com/2019/04/
https://www.sailnet.com/threads/rear...ost-2051708844
I have shop manuals and such that I found on line if you are interested.

[theglo]

Originally Posted by wsmurdoch

Our KBW10 (the Yanmar version) failed in Morgan's Bluff in 2019. We sailed the boat into a slip at Palm Cay and had the transmission repaired by Marine Diesel Ltd in Nassau. The repair did not hold and the transmission failed again later in the trip, but with the help of Marine Diesel Ltd we made temporary repairs and continued on with our trip. On our return to North Carolina I ordered parts to fix the transmission myself, but with the strong advice of a nearby retired long term Yanmar mechanic, I sent the transmission to East Coast Marine Transmission in NJ for a rebuild. We have had no further problems.
https://irish-eyes-to-the-bahamas.blogspot.com/2019/03/
https://irish-eyes-to-the-bahamas.blogspot.com/2019/04/
https://www.sailnet.com/threads/rear...ost-2051708844
I have shop manuals and such that I found on line if you are interested.

I just scanned your blog and it looks like you were in a similar position to us! Would you recommend Marine Diesel LTD? I'll call them Monday if so and get them started.

I think I've ruled out every "Easy" fix today. I've noticed the ATF fluid was filled a little high. Tomorrow AM I'll try to lower the level to exactly the full level, and see if I get lucky.

[wsmurdoch]

Would I recommend them? That is a difficult question. They removed my transmission, repaired it, and reinstalled it. The work required several 'special tools'. One was a specially made socket that should be used to tighten the nut at the rear of the transmission to (if memory serves) to 75 ft-lb. They did not have the socket and did their best. The nut later loosened and backed off. With their telephone assistance I reinstalled the nut sealing the transmission with silicone caulking and preventing the nut from backing off again with red loctite even though it was again not properly tightened. That repair held. So, we completed our planned stay in the Bahamas, we entertained guests aboard for a week in Georgetown during the Family Islands Regatta, and we returned to North Carolina without any additional transmission problem. They turned what could have been the end of our trip to the Bahamas and a sail home without an engine into a simple unpleasantry. I call that success.

PM me an email address, and I'll send you copies of the invoices for the work.

[theglo]

pm sent, thx!

[dlane1181]

We had a very similar issue with an older Hurth transmission 3-1/2 years ago in route from DR to PR to set up for our transatlantic passage to Spain.
Bottom line: Helpful and knowledgeable local mechanics in PR burned 3 weeks searching in vain for replacement clutch plates for us or a used transmission from the many hurricane-damaged vessels in the region. We ended up buying a new ZF transmission in Miami.
These small transmissions are surprisingly affordable (in boat terms, even with freight charges), and swapping them out was not difficult on our boat. The new transmission has been trouble free, and boat performance under power noticeably improved.
In retrospect, we wished we had gone with a new transmission right from the start.

[flyingnut40]

I had a similar situation with my HWB100 (same tranny) and the problem is actually the thrust washer for fwd. clutch pack wears thin and does not provide enough pressure on the discs. You could likely get by with a new thrust washer, but since the trans. has to come apart anyway why not buy the rebuild kit and do the whole thing?
Kit was about $500 on eBay and that includes clutch discs and friction plates, thrust washers and shims, gaskets and seals. The trans. Is easy to remove and the case comes apart with a 1/2" wrench. The only special tool you might need is access to a small press.
There are several YouTube videos if you search Hurth HWB 100 and you'll know what you are looking at. One guy even made an extra clutch disc out of a piece of steel to provide extra pressure on the clutch pack..... Mickey mouse way to compensate for thrust bearing wear but it worked at the time but would surely fail when the thrust washer finally wears to nothing.
My rebuild cost me $500 plus I replaced the drive plate for $120
Good luck!

[peter loveridge]

I went through 5 of these, one rebuilt one only lasted 25 hours. I eventually replaced it with the twin disk same size one which is a drop in fit, though the cables are on the opposite side. My first one was made in Germany and lasted 15 years. The later ones made in Slovakia or Italy and didn't seem the same. The instruction manual of the first on was somewhat unclear and recommended a LH prop. This is wrong and resulted in the transmission being in reverse when going a ahead. ZF say it can handle the same power but there's an extra cog in the power train and it makes more heat. The last time it failed I was at NE harbour in Maine , on the way to the Bahamas and Morris Yachts helped me out and took one off a similar size Universal. Their mechanic was an ace and changed the whole thing in less than 2 hours, It went all the way to the Bahamas and back to Nova Scotia without issue. When I got back to NS I changed it to the Twin Disk Technodrive 40 ( name might not be quite correct) which has had no issues. I've kept the one I got in Maine as a spare, and keep it on board, and , by now, I could certainly change it myself. The small ZF/Hurth transmissions are known to be unreliable ( Foley Engines says they're only good for 1000 hours) . The TD one costs about 50% more up here, but worth every cent

[Rumrace]

Before you buy a transmission did you confirm cable and cable clamps Steve working. Check the throttle cable ends and proper lube on both cable discs. Check the linkage on transmission.
It sounds like your not engaging. While in a simple cone dog or cup clutch forward will wear out and reverse will work.
Some, Clutch wear on Sailboats due to sailors over propping boats while power boaters rarely over prop a boat cause they got the hull speed / rpm redline memo.
Another tragedy for sail boat transmission is idling a high speed while the owner treats the engine like a 8kw generator only putting out 1.5 k. This heats up the transmissions without the benefit of its cooling. Worst time for a clutch is spinning freely then not landing square.

[sail34]

I have the same problem. The clutch pack in your transmission is worn on the forward side. I recently switched the forward and reverse clutch packs and was able to continue in the Abacos where I hauled out. I have new clutches waiting for when I return. the clutch pack were about $400 US and they came with 8 sintered bronze discs, 8 steel plates, seals and a thrust bearing and took about a month to arrive to Marsh Harbour. I am familiar with my trans as I had rebuilt it 12 years ago. I don't know how comfortable you feel tearing a transmission apart, it can be done but it isn't easy
Good luck
Cheers

[stormalong]

Originally Posted by Rumrace

Before you buy a transmission did you confirm cable and cable clamps Steve working. Check the throttle cable ends and proper lube on both cable discs. Check the linkage on transmission.

Yes, Be sure that the lever travel is correct. Take the shift cable off and shift directly. If that shifts consistently your linkage is not right. The shift lever can go further than the engage position and work fine so you could be shifting father than needed in reverse and not far enough in foward.