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jimgo 03-22-2013 11:59 AM

Hurth Transmission not Engaging
Our boat (1980 Allmand 31 with a Universal 5416 diesel) is being moved North by a captain, and he almost has her to the slip where I plan(ned) to take over. Almost. He was within a few miles of the slip and under power when the boat just wasn't moving any more. The engine was running fine, and had run fine for a day and a half, but then suddenly the prop wasn't turning any more. He said he tried shifting the transmission by hand, thinking perhaps the problem was in the linkage somewhere, but that didn't help. He's having her towed (glad I bought TowBoatUS!), and going to be looking at the problem a little more while he's waiting. I thought I'd see if anyone here had any suggestions, too. I don't believe there's any transmission fluid aboard, so he can't just check the level/change the fluid, which will probably be my first task when I get to the boat. Is there anything else he could try? Anyone have any ideas about what might be keeping the transmission from engaging?

deniseO30 03-22-2013 12:14 PM

Re: Hurth Transmission not Engaging
the fluid, dot 3, needs changing every season, Mine did the same thing and was fine since the fluid change. I have the same engine too. the shift cable may need to be adjusted also. Keep in reverse when sailing of not using the engine.

jimgo 03-22-2013 12:53 PM

Re: Hurth Transmission not Engaging
Thanks Denise! I don't think that was changed recently. I'll buy some and change the fluid.

I read on the Foley Engines site that they recommend Redline Synthetic or their own, Foly Hytork fluid. Do you remember the kind you used?

Hurth Marine Transmissions: The Ins and Outs of Basic Service | Foley Engines

Faster 03-22-2013 01:55 PM

Re: Hurth Transmission not Engaging
Careful about any dealings with Foley... Hurth gears use ATF... and not much of it!

jimgo 03-22-2013 01:57 PM

Re: Hurth Transmission not Engaging
Thanks for the warning. I stuck with ATF.

deniseO30 03-22-2013 01:57 PM

Re: Hurth Transmission not Engaging
Just ATF transmission fluid. here's a pdf.

jimgo 03-28-2013 07:54 PM

Re: Hurth Transmission not Engaging
Thanks again, everyone! We filled the transmission last weeked while we were there, but then the engine wouldn't start - there were problems with the starter. We got the starter off today and found someone who could do a same-day rebuild. That went well and was less expensive than I had expected. Unfortunately, once we got the starter back in place and hooked up, we couldn't get the throttle to shift into forward or reverse. It seems as though the Hurst transmission essentially exploded (internally) sending pieces into the engine which got sucked into the starter. So, now the engine is heading to a marina for repair; hopefully it will "just" be the transmission!

I've read that the original transmission (mine is an HBW 5) isn't made anymore. What's a good replacement?

Faster 03-28-2013 08:11 PM

Re: Hurth Transmission not Engaging
Marine Transmissions, ZF/Hurth Marine Transmission Sales

For a listing of ZF/Hurth gears...

When you say you 'filled' the gear.. be aware that 'full' is a mark only about 1/4 inch up the dipstick, and should be checked without threading it in.. ie.. drop the dipstick in the fill hole and let it rest without turning it in. They only take about 1/2 liter or quart ( possibly less for your smaller model).

Whatever gear you chose, be sure to check the exit angle wrt to the engine plane, the adaptor/bell housing pattern, crankshaft spline, overall length and coupling bolt pattern for compatibility. Large differences can lead to a new/modified prop shaft and coupling, mount relocation, etc that can cause costs to spiral out of control.

jimgo 03-28-2013 08:21 PM

Re: Hurth Transmission not Engaging
That's why I had hoped to find a direct replacement.

PorFin 03-28-2013 09:06 PM

Re: Hurth Transmission not Engaging

Before you get ahead of yourself, wait until the tranny's removed and you know exactly what has failed.

Besides the tranny, the broken bits could also be from your damper plate. If it failed, then your tranny may not need to be replaced.

Like Faster advises, the whole drive train needs a good look over.

The ZF boxes are pretty much the same as the old Hurth boxes. The gearing ratios are a little different, but the dimensions are the same. You should double check the dimensions, but I think that the ZF-10M would be a bolt-in replacement. I know it's a bolt-in for my HBW-100, and I think all the smaller boxes were built using the same cases. If you wind up replacing the tranny, you will need to verify what damper plate you need. Check the diameter, the bolt pattern and the input shaft configuration (# of splines and dimensions, e.g., mine's a 10/29/39.

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