Can't engage forward gear - WE'RE STUCK!!!!!!

Re: Can\'t engage forward gear - WE\'RE STUCK!!!!!!

Its me again.
Sorry I must go now as I am starting the day skipper practical this eve and will be away for a week.
Will have a look for the pdf I have on Hurth when I get back
Cheers, C_W
 
Re: Can\'t engage forward gear - WE\'RE STUCK!!!!!!

The following company handles Hurth transmissions:
www.asapsupplies.com
The prices aren't too bad, but you could wait until tomorrow if you don't want to ruin your Sunday! I'm told these people are very helpful and clued up.
 
Re: Can\'t engage forward gear - WE\'RE STUCK!!!!!!

FWIW I had an oil leak on my box ..I was the small seal on the gear selector shaft ( item 8) as shown in 2tizwos diagram

I dismantled the gear selector assembly and replaced the seal.

on re assembly I made a new gasket and all seemed ok ..but then I had trouble with gear selection as you describe.

I was concerned because I had no trouble prior to changing the oil seal.

I took it all apart again and although there was obvious ware on the selector due to age I felt it was to sudden for the box to fail because I disturbed the selector shaft.

on inspection I noticed that the new gasket I had made was very slightly thicker than the original (almost paper thin).

The original gasket was ok but was oil saturated.however I decided to put back the original gasket and get a new one when possible.

When reassembled all worked ok and I never had any re-occurrence

I feel sure that the tolerances in this assembly are very critical especially with age.

I did notice that a small amount of travel of the selector shaft (in and out) (Not Rotational) and I think my home made gasket allowed to much travel. (new gasket to thick)

Try pressing the selector leaver/shaft in as you rotate to select.

If by any chance or luck this is your problem DO NOT try to just tighten the assembly with the four bolts as this may strip the aluminum threads in the box

As said The above Is what I experienced

Good luck
 
Re: Can\'t engage forward gear - WE\'RE STUCK!!!!!!

SPEAK TO MIKE AT LANCING MARINE 01273410025 I AM SURE HE WILL SORT YOUR PROBLEM ONE WAY OR ANOTHER.
 
Re: Can\'t engage forward gear - WE\'RE STUCK!!!!!!

I don't know this particular gearbox but if it is a hydraulic gearshift then perhaps there is a blockage in one of the oil feed lines to the forward clutch.

This is assuming that the oil level is correct.
 
Re: Can\'t engage forward gear - AN UPDATE!!!!!!!!!!!!

AN UPDATE

Firstly apologies for not responding to the previous replies sooner. Internet connection here is feeble on Sundays.

This morning I had a friend over who is an ex Naval mechanic. We had another look at the gear box and noticed something significant that immediately crosses off some of the causes suggested above:

When engaging the gear at the gear box and putting into astern, the gear engages no problem. This we know. When engaging into ahead, however, we noticed that the shaft was actually attempting to turn. It turned very slowly, then stopped, then turned a little more.

So, it is clear the gear IS engaging, but to what extent we're not sure. I'm not familiar with the mating system but perhaps it is not being pushed far enough in.

The symptom of the gear working ok after half an hour of motoring would suggest that after the whole box has heated up the mechanism works ok or the oil is viscous enough to operate the mating system correctly.

To answer the remaining questions above:

Paul: yes we do sail with the gear in reverse and yes, the gears are ok after half an hour of motoring, once we've finally engaged the forwards gear. I'm very interested to know why you ask this.

CW: Your first suggestion of the selector hub sticking against its spring loading could still be true, so says my mechanic friend. Perhaps after the oil has heated up this becomes less of a problem? The dipstick in the diagram (19) is exactly where mine is - it looks very similar so why could it not be the Hurth 50?

Billskip: no oil leaks as far as I can tell.

Mike: It's not hydraulic.

Tiswoz & John: thanks for those links and images. It's a good start (though I could do with knowing what the numbers refer to in the exploded diagram). I'm on GPRS internet connection here so the pdf is still loading up.

Finally it's worth noting that I am based in Turkey, a country full of tractors and boats, where finding a replacement gear box shouldn't be a problem. You'd have thought that, wouldn't you............
 
Re: Can\'t engage forward gear - AN UPDATE!!!!!!!!!!!!

The Hurth/ZF gearbox has two multiplate oil immersed clutches which are engaged to give either forward or reverse direction. You probably use forward more than reverse so that one will wear first. Whilst the parts may look fine as wear takes place some thickness will be lost from the metal plates and the clutch will no longer be sufficiently loaded to grip and transmit torque. If the plates warm up they may expand sufficiently to grip a little but none too well or reliably. Two years since an overhaul is not long but how extensive was the overhaul? The gearbox is rated for 'pleasure use' or a certain number of hours which you may be going through relatively rapidly. Do you use it a lot?
ALT316901.jpg
This is a picture of an overhaul kit for this gearbox showing the plates. $150 on ebay. The clearance is adjusted with shims. Do your mechanics have a manual giving the necessary clearances?
 
Re: Can\'t engage forward gear - AN UPDATE!!!!!!!!!!!!

Hi Tizwoz,

I'm afraid I don't know the answer to some of these questions, though of course you are right that we use forward a lot more and yes, as liveaboards, we are using it a lot. However this is a problem that has never really gone away. OK, the gearbox was working well after the lobe was rebuilt but I don't think this is the problem any more as they've taken it apart and looked at the clutch.

The problem I have here in Marmaris is that there are no real 'known' gearbox experts. The only people recommended are the same guys who worked on our unit. God only knows if they used the correct overhaul kit. I couldn't ask them as they do not speak a word of English.
 
Re: Can\'t engage forward gear - AN UPDATE!!!!!!!!!!!!

Good evening,
just one more question - what happens if you start the engine while reverse gear is selected, can you then select forward with minimal problems?

rgs
Paul.
 
Re: Can\'t engage forward gear - AN UPDATE!!!!!!!!!!!!

Having had to have our Hurth 50 replaced, I was later told that the plates can be bought from Peugeot car dealers. Apparently they use the same plates as Hurth, and perhaps not surprisingly, they come cheaper.
 
Re: Can\'t engage forward gear - AN UPDATE!!!!!!!!!!!!

Paul - stop being cryptic! Tell me what you're getting at! I haven't tried starting the engine in reverse, except once when I forgot to put it into neutral. I'm not sure starting it in reverse is a good idea......is it? What could I expect to happen?

At the moment I can't try it out because yesterday, after my last post, the boat yard originally responsible for the failed repair job actually sent down a mechanic from Marmaris to take the box out and finally send it to a man in Izmir. They are paying for all expenses and any fixes that will solve the problem, so I can't complain at their fairness (even if I can complain about them not actually fixing it properly).

Obviously I will update you all as and when. In the meantime I just have to amuse myself in the marina for a few days. Bit weird after spending all summer at anchor. Not sure I like it. /forums/images/graemlins/frown.gif
 
Re: Can\'t engage forward gear - AN UPDATE!!!!!!!!!!!!

BTW - Tizwoz and Clyde - it's a Hurth 250. I confirmed this with Oyster who even had on record not just the engine and gearbox make and model, but their serial numbers too. I thought that was quite impressive!
 
Re: Can\'t engage forward gear - AN UPDATE!!!!!!!!!!!!

When I spoke with Cliff at winchservicing about my steering gear, he sent me a pdf of Moodys original job sheet for it ... equally impressive!
 
Re: Can\'t engage forward gear - AN UPDATE!!!!!!!!!!!!

Sorry I wasn't trying to be cryptic.
Its my engineering mind, I like to know as many of the facts as possible before committing to a solution.

It appears that you have it all under control as it could very possibly be a set of worn drive disc's.

My interest was aroused when I read that you had established that that was an improvement when the box warmed up.
I would have expected a different reaction as the normal thing for oil when warmed is for it to become more viscous (gets thinner), therefore gearboxes with multi-plate oil immersed clutches tend to loose rather than gain drive when warm or hot.
Another poster suggested that the plates could be expanding due to the heat, and while I have no evidence that this isn’t the case I personally would be surprised if it was this which led to the improvement in the performance of your gearbox. Of course we are all working on the theory that you have the correct grade of oil installed.

My questioning was trying to establish if you were suffering with worn drive splines, which could cause the gearbox to stay in neutral while selecting drive, this can sometimes also feel like you haven’t engaged gear as the box doesn’t seem to click or clunk into gear.

It is possible to lock up a gearbox by sailing with reverse engaged, this loads stress into the box, then when pushing it into neutral, starting the engine and selecting forward gear, the gearbox drive plates still haven’t fully engaged due to the splines binding together and the Belleville washers not being strong enough to close up the entire clutch pack. To get over this you can start the engine whilst still in reverse which unlocks the stress on the gearbox which causes the splines to bind on the drive plates, and so enables neutral and forward to be selected after with no problems.
In answer to your question starting in gear causes no mechanical problems as the prop is free to spin in water unlike a car which would move because of the physical rotation of the tyres on the tarmac.

Sorry for the long winded answer, but you did ask……………………

Again, its only my thoughts, and I am certainly not saying that anyone else’s advice or solutions are wrong.
I hope that upon your gearbox returning all your problems are cured.

Happy sailing.

Paul.
 
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