Gearbox problem any clues?

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crazy4557

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My boat a Targa 43 has 74p's andZF280 gearboxes fitted.
I went out yesterday for a fishing trip and cruising along at about 20 knots and suddenly slewed to the right and almost stopped. Sort of normal symptons for picking up a rope which was my first thought but engine not stalled! Immediately pulled both engines into neutral and had a peer over the back but no floating rope/debris to be seen.
Tried port engine and no problems with drive, in and out of reverse all OK. Starboard engine did engage reverse OK and I attempted to slowly reverse to maybe unwind rope:cool: but to no avail. Tried to go forward and neutral light comes on, engine revs but no drive. Looking in the engine bay and Prop was turning slowly on it's own probably by the motion of the water.
Limped back to my berth on port engine and tried again but engine runs fine but no drive just defaults to neutral. Walked away at this time to sleep on the problem and have a chat with VP.
This morning I started engine again and got forward/reverse no problem :encouragement:so went for a run out to see what happened...same thing. Tried to accelerate but black smoke and whole drive doesn't feel right if you know what I mean. Then same fault...starboard engine defaults to neutral.
I had the boat lifted to check for rope/net but nothing and props OK, shafts true and spin freely.
Gearbox has plenty of oil, nothing in the bilge to show signs of the issue. Gearbox did not feel hot to touch either when I returned as I checked this on returning to the berth.

So, only thing we have done over the winter is change the leaking gearbox oil cooler, change gearbox oil. VP thinks this possibly could be the issue as it's the only thing that's been tampered with.
 
Sounds like it could be air locks in the oil especialy if it been changed, the filling procedures on some boxes can be fairly critical.
 
I suspect your drive plate is OK but sounds to me like your gearbox has died. If you are getting black smoke sounds like its tightening up internally - not good.
Try these guys for a reconditioned gearbox http://www.mitgroup.co.uk/. I used them a few years ago and they were very helpful. I spoke to a Paul Masey.
 
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Chris_d said:
Sounds like it could be air locks in the oil especialy if it been changed, the filling procedures on some boxes can be fairly critical.
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VPFitted a new oil cooler that came from Coastal Rides, maybe it could have a flow problem? I'm going to swap oil coolers and see if the problem moves to the other engine.
 
crazy4557 said:
VPFitted a new oil cooler that came from Coastal Rides, maybe it could have a flow problem? I'm going to swap oil coolers and see if the problem moves to the other engine.
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Stop!
You might contaminate the good gearbox if the oil has debris in it.
Get a steel hose nipple/connector and join the two oil hoses together temporarily, try a short run but monitor temp closely. Its unlikely to be the cooler though given the symptoms. Get an oil pressure gauge connected somewhere in the system for starters.

Edit . I am not too familiar with this gearbox, Google images show a variety of control valves or solenoids to control the gearbox, I would suspect that's a good place to start.
 
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Do you get any error codes on the edc panel?

Had a similar(ish) thing happen to me once. On starting up the stb just gave an error on the edc. One of the solenoid thingies on the gearbox was hot as it defaulted to reverse. Re-calibrating the throttles sorted the issue and it hasn't re-occured since, touch wood.

Black smoke could be the the port engine working for the both of them? Mine may not be the issue in your case but could be worth trying the re-calibration. Google should find you the procedure on how to do that, I hope. I'm afraid I can't remember the exact sequence anymore...
 
Have you an oil pressure gauge? If not it would be best to check with one, there's an oil strainer fitted and can possibly get blocked, I'd be surprised if its anything to do with the cooler but an easy thing to eliminate before removing the box, if you need a 280 there's plenty of s/hand ones for sale. MIT can put on their test rig for fault finding and repair to very high standard, talk to Paul Macey and explain the problem, he's allways got the time to talk about what to do before asking for gearbox to be sent in.
 
I cannot see how a gearbox can overload an engine .
I have discussed with Andy various angles on this .
The boat and box was fine on a previous sea trial, the previous cooler was cracked so a coastal rides unit was fitted by me but supplied by Andy .
Then the problem arises, so is the cooler faulty nit allowing a good flow of oil to the clutch packs ?
Has the cooler contaminated the valves or clutches or internals and damaged the box?
Was the cooler new or from a damaged box that could have bits of metal in there ? Who knows.
One thing is I cannot see how a gearbox can overload the engine.
If the clutches slip and fail there is less load on the engine so it won't smoke.
Could oil be fed to both forward and reverse clutch at the same time , maybe if there is either an electrical fault on the wiring or a split in the casting of the valve block . Early 74/75 motors had a wiring mod on the edc loom as some examples did have dual engagement issues.
So lets wait and see what's gone wrong .

Correct sae 30 oil used on service, sea trial carried out , all good after many hours work on repairs and servicing , boats don't like being stood not used, after this the gremlins come out go play.
 
There is no feed back to tell the edc system if there are any problems with the gearbox. The only thing the edc monitors is the continuity through the solenoid coils. To test the mechanical side of the gearbox you can engage gear by manually operating the valves. It is explained in the operators manual.
 
Does anyone know why the EDC defaults to neutral and if so what problem would there be to make it do this?
That's the answer I'm looking for!
This is the main issue so if I can get that answer we can move on.
My thoughts on swapping oil coolers was purely to eliminate the changes we have made since it's last use. I also wanted to swap the solenoids over to see if the problem followed.
When the gearbox is cold it works fine. Gear selection is working correctly, forward/reverse selects and no fault codes shown. I was able to manoeuvre out of my berth with several forward/reverse applications (it's tight) motor out about a mile or so at tickover or just above. First application of power and it spits it's dummy and goes into neutral on that gearbox.It seems that when it warms up/power is applied then it defaults to neutral.
Shaft spins manually and feels 100% normal, no tight spots this I checked when lifted yesterday etc. Engines appear normal.
 
Remove the solenoid coil for astern from its shaft, but leave connected electrically. Seatrial, has engine overload gone? Can you check with multimeter or test light if both solenoids are being powered simultaneously? If you can eliminate an electrical control problem, as mentioned above there may be a mechanical override for the solenoids to try.
Edit we need to confirm oil pressure ahead/astern/neutral hot and cold
Can you extend the wiring loom to solenoids from port to stb and vice versa, that would show if problem follows across?
 
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Lots of experts on here but I have come across, this problem on more than one boat, the gearbox will work all day (if you want to go backwards) but ask it to go forward and as you say it spits it's dummy, I am referring to Ford engines fitted with Borg Warner boxes, and these are very low technology, cannot speak for the new fangled types with Computers. What colour is the fluid in the defective box? The prop shaft will spin easily, as when the gear is in neutral there is no connection with the engine, all you are doing is shifting gear oil around. IMHO I would remove the box and get checked out.
 
omega2 said:
Lots of experts on here but I have come across, this problem on more than one boat, the gearbox will work all day (if you want to go backwards) but ask it to go forward and as you say it spits it's dummy, I am referring to Ford engines fitted with Borg Warner boxes, and these are very low technology, cannot speak for the new fangled types with Computers. What colour is the fluid in the defective box? The prop shaft will spin easily, as when the gear is in neutral there is no connection with the engine, all you are doing is shifting gear oil around. IMHO I would remove the box and get checked out.
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Fluid is nice and clear as it's new. Trying oil cooler change and then change over solenoids if those don't help then gearbox off and get that checked over.
 
Be careful about changing the coolers over (I wouldn't). Don't assume that the last thing changed is the cause of your symptoms. There is logic in that choice but no science. The symptoms you describe are very unlikely to be oil cooling related. You need to check out the behavour of the gear selection solenoids before swapping coolers or pulling the gearbox off. An earlier post had some ideas about isolating the reverse gear solenoid. If you aren't sure how that all works and how to test it electrically - consider getting some help. Just swapping parts is what back street garages do and if you get it wrong it could be very expensive.
 
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As said before, there is no feedback to the EDC system from the gearbox. A mechanical fault in the gearbox will not tell the EDC to select neutral. I think you are looking at an EDC fault.
 
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