ZF 6 M, ZF 10 M transmissions

[sv.antea]

This is scarry. 6 years ago I noticed my Hurth 50 gearbox (on a Universal M25) was reluctant to go into forward. I was in the Med and shopped online for replacement. At that time ZF6M and ZF10M were recomanded replacement for the discontinued Hurth line, both were around $1200 online, but I couldn't fined a convenient dealer and was in hurry to get back home. Since I came back, I kept putting replacing the gearbox, because I was not doing any serious cruising and if I tried many times, eventually the gearbox did go into forward and would work happily for hours. Now it got pretty much impossible to shift into forward and search online came up with prices from $1800 to $2200. Worse, most of the websites said they are out of stock and the ZF manufacturer website lists ZF12M as the smallest transmission they offer for 2016. What is happening?

[Schooner Chandlery]

Call up these folks and get the scoop. They have a fellow who really knows Hurth and the follow on ZF http://www.merequipment.com/products...CategoryID=134.

Other thing--an oversized Hurth or ZF is not a bad thing.


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[sv.antea]

Thank you Schooner, I will contact them.
I have asked the forum previously about the problem I have been having with the transmission, namely it not going in fwd gear for many tries, but once it does, it doesn't slip and works untill I put it back in neutral. I have rebuilt the transmission in 1985 after salt water got inside and it was working fine untill 2010 and with the occasional reluctance since. I was hoping my previous post would get a response from someone with inside knowleage of the intricate clutch system of springs, ball bearings in their curved tracks and probably involving the innertia of the hubs (I suppose the inertia is stlill in good working order, lol). The responses mostly spoke of worn out clutch plates and slipping, which may be realted, but not exactly my case.
Since then I came across a thread discussing the same problem, but the consensus there was "you need to buy new transmission".
ZF6 was presumable a slight upgrade to Hurth 50, while ZF10M is much sturdier and slightly larger, but could be accomodated in my very tight installation. (It's ~1" longer). Haven't checked ZF12M dimensions yet, but any increase in size will not work.
I could rebuild again, but it doesn't seem outside of clutch plates, seals and gaskets, spare parts would be available. It's possible that replacing the clutch plates will solve the problem, but I'd hate to find out otherwise after buying the kit.

[sv.antea]

OK, I have found the answers and it is not pretty. Indeed, the ZF6M and ZF10M haven't been in production for long while, hence the sharp rise in prices and decline of availabilty. The ZF 12M is too big for my elaborate shoe horn fit and different vertical offset and different gear ratio. I will be rebuilding the old HBW50 one more time, likely using some used parts.

[ErikFinn]

Thanks for posting antea. It would be absolutely fabulous if you could post a thread about the rebuilding with some photos.

[Schooner Chandlery]

Sorry to hear about your situation of having to use used parts. You might want to check out the boatdiesel forums. I'm a paid member there and find the site useful. You may find parts source or someone to help you out in other ways there.

I have purchased used parts as well as new old stock parts via eBay with success but not for our current boat.


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[lamadriver]

ASAP supply , shipped a new zf10 from the uk to Asia for 800 usd

I am in the process of fitting the gearbox with a aftermarket cooler



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[Sailmonkey]

Have you looked at a twin disc/techno drive 340 gear box? It's a bolt on replacement for the zf10. May work for you.


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[sv.antea]

Thanks Sailmonkey, I will definitelly look into that. After cycling through the options available on the internet, I came to the conclusion that someone is bound to step into the gap and I should just wait. So TwinDisc did? Let's see if it will fit my insane shoe-horn install and how much it is.

[sv.antea]

Yup, Twin Disc Technodrive TMC 40 P is the new close equivalent. Comparing to HBW 50, it is probably 10mm longer, the the vertical offset 5.5mm larger, the shifter is on port side instead of starboard, the splined input shaft sticks out 28 mm further, but the splines start same 21mm from the housing. Amazingly enough, it will probably fit.

[sv.antea]

Schooner, I have carefully compared dimensions HBW50 and TwinDisc TMC40P and everything looked fine untill I checked the clearance for the shifter lever. There I am missing about 6mm. There is hull there on my sailboat. I just paid $25 for entry level membership BoatDiesel.com, hoping to view a page from the shop manual to see if a protruding stud and nut can be replaced with a bolt, as it is on larger models, but when I got to the page, it told me "members only". Turns out to view that page, I would have to pay $100 for level 2. I wonder if you have level 2 memebership and be willing to copy the shifter detail on page10 and forwarding it. Thanks anyway, Stan

[sv.antea]

Everything looked doable with the switch from Hurth HBW50 to TwinDisc TMC40P, until I checked if I have room for the port side mounted shifter lever.
Ouch. There is the hull there on my boat. The lever is much lower, even with the output shaft axis and not only stick out further, but actually telescopes out further 5mm when taken out of neutral. There is this utterly unnecesary looking stud and nut sticking out of the shifter shaft. On next larger model there is a head of a bolt instead - it doesn't stick out at all. So I want to know if I can replace the stud and nut with a bolt, or just cut off the offending part of the stud? It would fit with that. Any ideas?

[SR Tech]

Sorry to scrape up an old thread, but the ZF10M is an old transmission.

A friend of mine is trying to repair his old ZF10M in his fishing boat. He needs seals to finish, but all I can find are ZF seal kit # 3304 199 003, but no one has stock. Can anyone help me find the actual seal part numbers, instead of the ZF part numbers? I cannot find a cross reference anywhere.

[Sailmonkey]

Why not just measure the OD, ID and seal depth and buy appropriate seals

[SR Tech]

Thanks Sailmonkey for the suggestion, I am waiting for those measurements, but thought I could try tracking down numbers while I wait. The boat and friend are a long way from here.

I found the main taper bearing numbers are L44649 with L44610 races, so perhaps someone will need those numbers one day.