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Hurth Noise in Fwd (Tranny Removal ?)

newgringo

Member III
Help again folks. After accomplishing 36 of the 38 high priority tasks for this wonderful 1986 E32-3 we bought in Dec 05 we are sailing! It is great and we are looking forward to a fantastic summer here in Puget Sound and parts North. But I am a worry wart. The Hurth Transmission behind the Universal M25 (which is a 1.8:1 reduction, yep 1.8 for sure) growls when in Forward gear. It is very noticeable at engine idle but gets drowned out by engine noise when the speed is increased. It has been doing this ever since we got the boat. Also it is much quieter when in reverse. First, How much of a concern is this? and Second, If I necessary can I remove the transmission easily without pulling the motor off the mounts?
Some transmission background. Right after we got the boat I drained the transmission oil and it was nearly dry. I only captured a few ounces of very dark oil (no noticeable metal/debris). I refilled with DEXRON III, ran an hour and drained to inspect for metal/debris. To my amazement the oil was clean. Refilled and have since repaired 3 leaks (drain plug gasget, improper vent and loose bolt). I watch that oil level closer than my morning coffee.
Any and all advice to help us have a smiley summer is much appreciated.
Jerry & Jean Riggs, Kingston, WA griggs@centurytel.net
 

hodo

Member III
trans removal

Hi Jerry, I'm not sure about yours, but on my e 30, I was able to remove the trans by sliding the prop shaft back, and removing the drive flange. It sounds like you have a bad bearing on the front of the output shaft. The reason I say this is because the load is forward on the shaft,in Forward gear. I would attend to this very soon, as it is much less expesive to buy bearings, seals and shims than a whole unit. Not to mention that we know these things always fail at the most inopportune times. I've done several of these, so if you need to , feel fre to e mail me. We will be in Kingston on the weekend of June 10 for a yacht club function,on our way to Sydney for the rendevouz. Are you guys heading up too? Good luck, Harold. S/V Mischief :devil: Maker
 

newgringo

Member III
hodo (Harold),
I sent you a couple emails but have heard nothing back. I have an experienced mechanic coming to look see to opinionize if I am just listening for problems that do not exist or confirm if I really do have a problem. Desire to keep in touch and will be looking for you and SV Mischief Maker in Kingston weekend of June 10.
Jerry SV Raconteur
 

newgringo

Member III
Today an experienced diesel mechanic listed to the transmission and after numer shifts FWD N REV power up power down etc he said he hears nothing to be concerned about. Said they just sound like that. Wonderful! I still have my concerns and with my mechanics stethoscope I can hear gears backlashing and, what I think, is copious amounts of gear and bearing rumble. The backlashing does go away as the engine is speeded up but the other noises remain and just get drowned out by the engine noise. So for now I am a happy camper. Thanks to all who offered suggestions. If anything else developes on this tranny I will post info.
Jerry in Kingston, WA E32-3 SV Raconteur
 

newgringo

Member III
Just an update. Now after the about 70 hours of running the transmission is still making all the annoying noises, but still working good. I sure appears the expert mechanic knew what he was talking about. But it still is noisier than units in other boats and my plan is to pull it this winter and rebuild it, just to make it quieter for my own satisfaction if nothing else. Onward.
 

newgringo

Member III
The noisy hurth ZF10M (1.792:1 ratio) in our E32-3 is out and in a million pieces on my work bench. The whole process of pulling this tranny out of the boat took about 8 hours including building the engine lifting jig, pulling the heat exchanger, etc. Not really a fun job at all. And, no, I did not find a reason for the growling noises in fwd gear :unsure: . But, it is educational! :) I'll decide tomorrow about rebuilding this unit or buying a new one for some $1060 plus tax here in WA. Anyone know of a better source for a new Hurth?
But some good news. Found a source of Hurth (and other) Service Manuals on line. For $6.99 this guy in Sweden emailed me a scanned 61 page image in pdf format of the factory Hurth Transmission service manual. I thought that was a deal. Whole process took about 30 minutes. His Ebay name is "rick573020" or you can email "info@linkadder.com".
 

hodo

Member III
Hi Jerry, These things are pretty straightforward to rebuild. It is important to get the correct pre-load on the bearings. There is a place in Seattle, that has parts and rebuilt and used Hurth trannys. E mail me if you like. Harold
 

newgringo

Member III
Well it is done and back in the boat. And it IS quieter.:) It now sounds like other Hurths which all seem to be noisy at idle till about 1200 rpm or so. I never did find a definite reason for the excessive annoying noises but if I had to guess I would agree with Hodo that the Forward Thrust Bearing was bad. It had an unusual wear patterns where the rollers contacted. All told this adventure cost me about $500 for parts which included all bearings, seals, gasgets and clutches. The job is straightforward but does require lots of bearing pullers and a press to reassemble the main clutch shaft, along with careful measuring of some clutch and bearing clearances. Would I do it again? Good question. The R&R part was the toughest since I had to raise the engine to get the bell housing off. I think I would try and avoid a repeat of this last 2 weeks. Now on to more fun chores. :D
 

newgringo

Member III
Used Hurth ZF10M 1.8:1 Fixeable and Available !

Bad news. The Hurth I carefully rebuilt which worked so well for 50 or so hours stopped engaging into FWD gear every time I tried! Yikes. Not knowing if I could fix it and with summer just around the corner, I put in a brand new ZF10M. I pulled the shift plate off the old one and do not see any internal problem or reason why it is unreliable engaging FWD gear. On the bench I can make it fail the same way and also get it to engage OK too. All I can think of that may be wrong is I changed the clutch shimming during assembly to agree with the overhaul manual, which may be wrong. So I "think" it is fixeable. And it is available. If any of you want a project, horse trade me something and it's yours. I can haul it to the PT rondeevoo. My email is griggs@centurytel.net
 
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