2001 Searay 340 8.1 zf Transmission

[rjrcmr03]

Hi first time posting but desperate. Has anyone ever removed a Hurth Trans from a 340 sundancer with 8.1L. If so how was it and do you have any tips. Thank you for any help.

[wingless]

There are many inspections and services that may / should be performed while the transmission is in-place and the boat is in the water.

Has the high-pressure hydraulic system been inspected per the FSM to determine the cause of the transmission stuck in forward problem?

On my 380DA there is not much room in-front of the transmission and it might not be enough to shift the transmission away from the engine to clear the input shaft.

Have the valve passages been inspected and cleaned to determine if those are contributing to the problem?

Also, the forward mounts are on the transmission so I would yank the engine / transmission assembly to avoid trying to support that end of the engine w the transmission out.

Does the prop / coupler rotate by hand w the engine off?

Here is a reply w/ information on fixing problems w/ this transmission.

[rjrcmr03]

Thanks for the help. I have not checked pressures because I have rebuilt a couple of ZF drives for the guys at the dock with he same type of problem. My problem is I can move the shifter at the trans forward or reverse but with the engine running it stays in forward gear and no neutral. If I put it in reverse it instantly stalls. Trying to put the trans in forward and reverse at the same time, not happening. I have found with theses that the clutch pack welds itself. Unfortunately it happens to be my boat this time which sucks to be me....I was looking for a way to pull the trans without the engine if it is even possible.

Thanks buddy for the help

[wingless]

Thanks for the information.

If the clutch pack is welded, then w/ the engine off is it "impossible" to rotate the prop or the coupling? Why does the clutch pack weld failure happen?

As was stated, even if the transmission could be removed, I have no idea how it would be possible to support the forward half of the engine w/ no transmission.

[rjrcmr03]

Yes with the engine off you can not freely turn the shaft. I think the biggest cause of failure is misadjusted shift cables. Meaning when you are in forward gear the manual valve is only partially in gear causing a low pressure inadequate amount of lubrication. Create friction between the plates and weld themselves together. If I have to pull this engine and trans together how hard is it? Just by looking around at it, it really doesn't look to bad. I am stubborn so I was trying to get the trans out by itself but I can't get the propshaft to release from the flange. I think the woodruff key is holding me up. Yes boat is in water. That is why I am trying to do this job in the water. I didn't want to end my season just yet.

[wingless]

IMO, I would not risk pulling the engine / transmission while the boat is in the water. The removal requires prop removal and requires that the shaft be slid back or out. If the un-retained shaft slides out, then there is a large hole at the shaft seal that will cause a big problem.

On my boat the transmission / shaft hub was a butt pain to split, when I first got the boat. Also, the prop / shaft was also a butt pain to split.

When I disassembled those parts, I lapped the parts so that they fit together properly. I also cross lapped the parts, so it doesn't matter how they are assembled. Now they come apart nicely.

I doubt is it the woodruff key. When they are apart, examine the contact surfaces. On mine there were two diagonally opposing contact points. Now the entire surface has an even contact.


If that were my boat I would disassemble the valve / pump while the boat is in the water for inspection, cleaning and assembly, per my prior post. That is an in-the-water service and it is "easy" to perform.

Good luck!

[rjrcmr03]

Sorry buddy I didn't mean pulling both while in the water. I was just talking about the trans. If I do both I am pulling the boat out of the water in which I will probably do. Now checking the Valve assembly why would that cause no neutral but cause it to try and engage reverse but stall? It wants to go in reverse when I select it, but can not get out of forward gear. feels like trans locks up in reverse causing engine to stall because it wont go out of forward.

[wingless]

Look at the pump and valve in my reply.

There are many small passages that could become obstructed and rendered inoperative.

It only costs time to disassemble, inspect, clean and reassemble.

The valve directs the very high pressure hydraulic fluid to engage / disengage the clutch disc.

It might be that the hydraulics are "confused" by inoperative ports.

[wingless]

Originally Posted by rjrcmr03

Sorry buddy I didn't mean pulling both while in the water. I was just talking about the trans. If I do both I am pulling the boat out of the water in which I will probably do.

The shaft passes through the transmission.

When the coupling is separated from the transmission, or when the coupling is separated from the shaft, the shaft may slide forward and back a small amount, about an inch. The travel range is limited by the propeller. The shaft forward motion is stopped by the prop contacting the strut. The shaft rearward motion is stopped by the prop contacting the rudder.

It would not be possible to remove the transmission in the boat w/o removing the propeller, sliding the shaft WAAY out of the boat w/o losing the shaft, then starting to remove the transmission.

Also, as had been stated, the transmission has the forward engine mounts, so something would need to support the forward part of the engine.

Please post pictures if this is attempted.

Don't forget to use seal protectors if the shaft is ever removed or installed, so the keyway does not destroy the seal in the dripless seal carrier.

[wingless]

Originally Posted by wingless

If the clutch pack is welded, then w/ the engine off is it "impossible" to rotate the prop or the coupling?

Originally Posted by rjrcmr03

Yes with the engine off you can not freely turn the shaft.

When the coupling is rotated w/ the engine off, is it hand-cranking the engine? Do you feel the compression strokes?

There should be resistance, but turning the prop by hand, or the coupling w/ a tool is possible.

What is the shaft / prop / coupling turning status on your boat?

[wingless]

How does the transmission fluid look?

Is it clear red w/o bubbles or foam?

When was the last change and when was the last filter replacement?

[rjrcmr03]

Yes there is a lot of resistance. Cannot turn by hand. If I force it to turn then I can get the flexplate to turn with it. "Its like having a direct drive" there is definitely something wrong internal to trans. I bought the boat in Feb.2013 Was told everything was serviced and looked it over to verify. Even the trans color was good and pink and yes to the proper level. I ran it all this season and put about 75hrs on it. I am going to dry dock and pull the engine and trans and call it a season

[wingless]

Thanks for the information. So the turning resistance is much greater on this transmission than on the other one?

If the transmission is engaged w/ the engine off, then turning the coupling should cause the engine to crank, permitting the compression pulses to be felt.

[rjrcmr03]

Yes turning the coupling turns the input shaft and turns the flywheel which turns the crankshaft all this with the engine off. The other trans no problem some resistance but so very little.

[wingless]

Originally Posted by rjrcmr03

Yes turning the coupling turns the input shaft and turns the flywheel which turns the crankshaft all this with the engine off. The other trans no problem some resistance but so very little.

Great information!!!

Thank you!



There is good news and there is bad news.

The good news is you have air in your lungs and you have a nice boat.

The bad news is your transmission is hosed and you've got to yank your boat, yank your engine / transmission assembly, disassemble your transmission and fix the problem(s).


On a good transmission the input shaft is powered from the engine and the control block directs the 312-377 PSI to push the input shaft to compress the clutch pack A (near the engine) to cause the output to rotate opposite to the engine, or to compress clutch pack B (away from the engine) to cause the output to rotate the same as the engine.

Clutch pack A directs the torque to the output shaft. Clutch pack B directs the torque to the intermediate shaft, then to the output shaft.

It sounds like your problem is that one clutch pack is always / permanently engaged. Then when shifting / moving the input shaft to engage the other clutch pack, the transmission stops the engine from rotating.

The path for the binding torque is input shaft => clutch pack A => => output shaft => intermediate shaft => clutch pack B => input shaft (opposite direction).

IMO, the BIG problem is that all these parts have been subjected to the very, very abnormal shock forces of stopping a big block V8.

IMO, all these parts should all be Magnafluxed, even if they look okay, because they have been abused and some may / will fail.


Download the Operating Manual and the Transmission Manual for your Hurth V-drive transmission.

Please post images of the failed parts.


Good luck!!!