Technodrive TM170 TM880A, TwinDisk engaging failure, low hours

[vas]

Re: port gearbox works only on reverse

Hi Vas

Been following this thread.

From my limited experience with Borg warner marine and AP vehicle transmissions, the low oil pressure indicates a large leak, most probably caused bt the forward clutch piston seal having failed.

it would be interesting if you could pressurise the appropriate oil gallery o n the shafts with air and work out if the wear on the housing is serious. Cant see how the casing wear would lead the drive to fail in one go, if it had gradually got worse, yes.

David,

yes, this is a valid point, loose all drive in one go doesn't really fit with worn diverter valve body and slightly worn (possibly!) rings on the oil pressurising point.
I'm afraid I cannot think of a way of testing/pressurising the fwd axle oilway.

However, I could do something that I foolishly forgot in the afteroon:
Fit again the gauge on the pump checkpoint and see how much it drops on engaging fwd and then reverse.
It may give some extra pointers.

Further, I don't think my other idea holds any water, namely grindings from the casting found their way in the oilway and blocked it not letting enough oil through to press the disks. If that was the case the pressure on the fwd axle pickup would be HIGHER not lower...

On one gearbox I had the forward clutch plate container ring failed,(item 40 in your diagram above) no drive forward, no noises etc as the bits stayed nearly in place , but the piston moved sufficiently for the resulting oil leak to cause the pressure to drop to near zero. Reverse only worked as well.

That was an instant failure as well.

This (although I definitely don't like it!) makes more sense engineering wise...
Would I expect to find big chunks of steel rings in the box when I emptied and replaced the oil? 'Cause I didn't find a thing!
Wonder what are my chances of doing such an operation with the box in situ. Should be possible to remove the axle mating plate (however you call that) and undo the bolts holding the thing together and open it up.
Is it possible or plain stupid as an idea?

other opinions welcomed!

cheers

V.

 

[superheat6k]

Re: port gearbox works only on reverse

It was about this time last year I had my stbd box lifted for a repaint, so the 70mm is from memory, possibly as short as 50mm, but probably closer to at least 60mm, however the diagram in the manual might show the shaft accurately to scale so use a known size such as a bolt head to scale the shaft length.

 

[david_bagshaw]

Re: port gearbox works only on reverse

David,

yes, this is a valid point, loose all drive in one go doesn't really fit with worn diverter valve body and slightly worn (possibly!) rings on the oil pressurising point.
I'm afraid I cannot think of a way of testing/pressurising the fwd axle oilway.

How about cutting up an inner tube wrapping it over the shaft and securing it with a jubilee clip, on the bits near the split rings.. then inflate, might be able to hear where the leak is with a tube in through the filler. better though would be....

A cheap usb endoscope camera on the end of a wire might give you a look in the box,

http://www.ebay.co.uk/itm/like/4010...ICEP3.0.0-L&ff14=122&viphx=1&ops=true&ff13=80

I used one last year to see injection timing marks which were not viewable by mirrors, as under engine brackets.

However, I could do something that I foolishly forgot in the afteroon:
Fit again the gauge on the pump checkpoint and see how much it drops on engaging fwd and then reverse.
It may give some extra pointers.

Further, I don't think my other idea holds any water, namely grindings from the casting found their way in the oilway and blocked it not letting enough oil through to press the disks. If that was the case the pressure on the fwd axle pickup would be HIGHER not lower...

yes you are right. The very fact the oil pump can produce the correct pressure for reverse, means if forward pressure is low, there is a leak. the fact the forward pressure is so low says it is a big, big leak. A medium leak, would have made the plates slip, which would have overheated the box, burnt the plate facings and blackened the oil , with a nasty burnt smell to it.




This (although I definitely don't like it!) makes more sense engineering wise...
Would I expect to find big chunks of steel rings in the box when I emptied and replaced the oil? 'Cause I didn't find a thing!
On mine all the the bits were still on the shaft, none broken, though a little bent.

Wonder what are my chances of doing such an operation with the box in situ. Should be possible to remove the axle mating plate (however you call that) and undo the bolts holding the thing together and open it up.
Is it possible or plain stupid as an idea?

Personally I wouldnt do it as probably the casings would need to move more than the distance of the input shaft., plus keeping dirt out on assembly would be very difficult.
Unbolt the prop shaft coupling, and push the shaft back. if still short of room, tilt the engine up at the back so you can lift gearbox back and over the now lower coupling.

other opinions welcomed!

cheers

V.

put thoughts in bold above

 

[NorthUp]

Re: port gearbox works only on reverse

Stop buggering about and strip the gearbox down to the ahead clutch plates and piston rings (which may just be rubber o-rings gone hard)!

 

[vas]

Re: port gearbox works only on reverse

put thoughts in bold above

thanks David

however as NorthUp "politely" puts it, no matter what, next step is removing the box...

Stop buggering about and strip the gearbox down to the ahead clutch plates and piston rings (which may just be rubber o-rings gone hard)!

OK, OK, we'll get there eventually. No time to embark in that right now for another week or so as wife is in freezing Sweden working and I have to taxi, cook and babysit the kids to school and various activities on top of job obligations...

Curious where the rubber o-ring is on this diagram though! Cannot even spot a proper seal anywhere but maybe it's me...

NorthUp, I guess you dismiss the case of worn piston rings at the diverter body being the culprit, right?

cheers

V.

 

[rbcoomer]

Re: port gearbox works only on reverse

9, 11, 32 & 34?

 

[vas]

Re: port gearbox works only on reverse

9, 11, 32 & 34?

R.,

all these are steel rings with a tongue/hook thing that work like piston rings, no rubber in sight.
Yes they are there to keep pressure up, but not something that can harden out of lack of use and fail.

cheers

V.

 

[rbcoomer]

Re: port gearbox works only on reverse

R.,

all these are steel rings with a tongue/hook thing that work like piston rings, no rubber in sight.
Yes they are there to keep pressure up, but not something that can harden out of lack of use and fail.

cheers

V.

Gotcha. Can't quite see how the oil loss can be here actually. I'm assuming the holes (if they are holes?) in the shafts are oil channels to lubricate the bearings and thus would be very small?

 

[NorthUp]

Re: port gearbox works only on reverse

Numbers 4 and 27, yes - they do appear to be metal rings, not the rubber ring found in some other makes.
Mea culpa..
I was also being bold!��

 

[vas]

Re: port gearbox works only on reverse

Gotcha. Can't quite see how the oil loss can be here actually. I'm assuming the holes (if they are holes?) in the shafts are oil channels to lubricate the bearings and thus would be very small?

the hole on the 30mm (approx dia) axle is around 2-3mm. Apparently oil is diverted to the hole and then oil travels through the axle and somehow exits and presses the 9 disk assembly in order to engage. Sounds odd, but unless I get all the pieces on a workbench I cannot fully grasp the way it operates.
The two metal rings on the grooves either side of the wider groove where the oil gets inside the axle are there to make sure all pressure and oil is driven inside the axle and not "wasted" around there. So if worn, in theory would cause low pressure issues, however that would be a gradual occurance, not a split second change in operation. Hence my continuing questioning of the process and possible failures.

Mind if it was a couple of hours job to remove it on the spot I'd probably have done it already, but splined axles, undoing rear engine mounts and levering engine up, pushing axle back, setting up props, small chain winches, etc, with boat in the water and holding with two stern lines and its own anchor (haven't organised a permanent bow mooring as yet for various reasons) is not ideal. OTOH, getting her on the hard on one engine is going to be interesting trying to push up and square on the trolley so better have both engines working fwd on that day.

cheers

V.

 

[vas]

Re: port gearbox works only on reverse

Numbers 4 and 27, yes - they do appear to be metal rings, not the rubber ring found in some other makes.
Mea culpa..
I was also being bold!��

no problem, you're (as all others) being very helpful, so not complaining if you're stating the obvious.
Although, I'd like your opinion on my last Q:

NorthUp, I guess you dismiss the case of worn piston rings at the diverter body being the culprit, right?

I'm talking about items 34 on the intermediate shaft. They are now the old ones as spares were wrong sized.

Personally I'm not convinced they are to blame as looking and feeling at them (with specs on!) don't look much different to the ones on the input shaft.

cheers

V.

 

[P4Paul]

Re: port gearbox works only on reverse

Numbers 4 and 27, yes - they do appear to be metal rings, not the rubber ring found in some other makes.
Mea culpa..
I was also being bold!��

no problem, you're (as all others) being very helpful, so not complaining if you're stating the obvious.
Although, I'd like your opinion on my last Q:

I suspect you will find that they are square section 'o-rings' rather than metal.

 

[vas]

Re: port gearbox works only on reverse

I suspect you will find that they are square section 'o-rings' rather than metal.

We shall see as decision taken to remove the box.

Got some prices an hour ago:
seal kit around 130euro
rings kit something similar
fwd or reverse disk set 250 each set.

Not bad if I can manage to take apart and refit successfully without any leftovers that is

will keep you posted as always...

cheers

V.

 

[P4Paul]

Re: port gearbox works only on reverse

We shall see as decision taken to remove the box.

Got some prices an hour ago:
seal kit around 130euro
rings kit something similar
fwd or reverse disk set 250 each set.

Not bad if I can manage to take apart and refit successfully without any leftovers that is

will keep you posted as always...

cheers

V.

Good decision, hope it all goes well and is easier than expected.

 

[david_bagshaw]

Re: port gearbox works only on reverse

my bet is 17 0r 40 have poped out allowing the clutch pack to fall out, pushed by the piston 5 or 28, which then lets out the oil pressure.


I will have 5 bob on the above please.

Good luck with the disassemble, better luck with putting it together again!

 

[vas]

Re: port gearbox works only on reverse

Good decision, hope it all goes well and is easier than expected.

cheers, looking forward to that!

my bet is 17 0r 40 have poped out allowing the clutch pack to fall out, pushed by the piston 5 or 28, which then lets out the oil pressure.


I will have 5 bob on the above please.

Good luck with the disassemble, better luck with putting it together again!

OK, I'll offer a decent meal in the best restaurant in Volos
[not paying travel expenses mind]

Should all these "hope it's easier than expected" and "better luck putting it together again" have me worried?

May have a go at undoing the basic things and trying to disconnect it on Sat, Weather seems good, if I can get a small winch I should be OK

Not exactly sure that disconnecting the box to the engine entails. Is it just pulling it out of a spline, or some other method that involves specialised tools or large sledgehammers?


cheers

V.

 

[steadyeddy]

Re: port gearbox works only on reverse

Good luck on Saturaday hope it all goes well:encouragement:

 

[vas]

Re: port gearbox works only on reverse

Good luck on Saturaday hope it all goes well:encouragement:

thanks, looks like I wont need much luck, as it took me an hour to undo all ancillaries (er, all two pipes to the cooler, and four bolts to the axle...) and undo the 12 M10 bolts that hold the box to the engine.
Pushed the propshaft around 80mm back, hit once with a hammer and gearbox easily moved out 3-4mm. Obviously spring loaded clutch doing its thing. Just in case i've got 4 bolts loose on till tomorrow morning that a friend with a small chain winch will come and give me a hand removing the box.

Btw, before doing all this hard work I moved the gauge to the pump pickup and checked what happens when I change from idle to fwd or astern (engine at idle speed or around 630-650rpm:

Idle: 330psi
astern: momentarily drops, then goes up to 380psi for a few secs and settles to around 330-340psi.
ahead: drops to 60psi, after a few secs starts going up to approx 100psi, and the axle starts thinking of turning. Give it a few more secs, pressure goes to around 110-120(max!) and axle turns slowly for as long as you keep it there.

Got a couple of min video on the mobile will probably upload sometime.

Looks like if we manage to lift it up to salon deck level I'll have a go at opening up and peeking in for anything odd (if I can see anything odd!)
Next step is to take the ahead axle to Vangelis and carefully dismantle it (with the service manual at hand...)

Anyone else wants to bet what's failed in there?

cheers

V.

 

[rafiki_]

Re: port gearbox works only on reverse

Reckon it's a seal Vas. Good luck with it anyway.

 

[vas]

Re: port gearbox works only on reverse

Reckon it's a seal Vas. Good luck with it anyway.

thanks P.,

but you really need a # to play, not a general "seal", which seal

anyway, we may know tomorrow

cheers

V.