Technodrive TM170 TM880A, TwinDisk engaging failure, low hours

[vas]

Re: port gearbox works only on reverse

I can't explain why you are not measuring pressure where you are tapping in, unless the port is somehow closed. The fact it engages astern but not ahead suggests it is a diverter issue. If the ahead clutch had failed it would gradually fail and slip first, not just not drive at all.

my hopes at least is the diverter
considering the 600h on the box and the hero to zero behavior of the box (from nicely planning at 2.1K rpm to dropping off the plane and going up to 2.4K rpm with no thrust whatsoever) it is unlikely to be just slipping...

I would do as Portofino suggests and withdraw the selector valve and inspect it. Make sure every where around is clean, and be thorough with cleaning any muck off before you put it back in. You might need new seals as these may swell up.

Just a thought have you removed the oil strainer and checked this is clean - large plug at bottom of box below the oil pump. This will drain the oil, so collect this and check for any metallic debris.

Your box is certainly very similar to the MG502.

I think I'll just do that and remove the stbrd selector and place it on the port box after examining the valve underneath it that is.

Oil strainer is after the suction pipe from the sump to the pump and just before the pump. Big 32mm socket to remove it, yes done it forgotten to post pics on the thread here it is:

you can see some debris on the towel

all the bits are magnetic and are in the following pic stuck on the two magnets of my tape measure (just to give the size of the debris):

I consider that OKish, haven't got a clue when the oil was last changed, will do so.


ah, and since I'm posting pics, check out another one with the two pipes outlet to the cooler on the right towards the engine block, return with the sensor towards the stern.

Couple more ideas:
Any chance box has WRONG oil (as in auto-transmission oil we use on hydraulic steering systems) instead of the specced 20 or 30 SAE thing? Would that possibly cause some problems that are now surfacing with some more serious damage?
On that, is it really that much of a difference between the auto transmission and the SAE30?

Only thing done on the port engine was remove and thoroughly clean all heat exchangers. New O-rings used all around so doubt sea water contamination (or rather sea contamination out of pressurized oil going to the sea) is an issue. Levels are spot on. Can anyone image any type of stupid mistake by my side, or other knock on effect a thorough dismantling and cleaning may have on a system like that?

cheers

V.

 

[vas]

Re: port gearbox works only on reverse

Swapping parts is luxury with a twin engined outfit -like a boat -and use full in diagnosis .A luxury not afforded in say a car ?
You don,t necessarily need to know how they (parts) work .

yes, very true, however I'm skeptical on making a move that may contaminate or affect the other gbox that works fine. I know long shot...
Main concern is that lifting the bleeding diverter axle and valve under it I'm afraid that the lower part may stay in or even worse some bits of it fall in the hole the wrong way around which would then mean removing the box and turning it around to "drop" the wrongly assembled bits out... That wouldn't be nice!

Another Q have you manually moved the shift lever after its disconnected ?
This is to eliminate "detent" position .ie the attached cable is preventing the valve fully clicking /engaging .
So when you rev up some oil squeezes through the partially engaged /lined up valves ?-leading to the shaft starting to turn

yep, made sure the lever travel and angle of rotation is identical to the stbrd one. Have a feeling it wasn't so before with problematic engine lever on astern moving a few degrees less than the other engine (obviously moving the other way) but will try again and establish at which travel angle oil starts moving towards the plates. Don't know how progressive is that.tbh

thank you both for the interesting pointers will hopefully test some/all of them and report again

cheers

V.

 

[rbcoomer]

Re: port gearbox works only on reverse

yes, very true, however I'm skeptical on making a move that may contaminate or affect the other gbox that works fine. I know long shot...
Main concern is that lifting the bleeding diverter axle and valve under it I'm afraid that the lower part may stay in or even worse some bits of it fall in the hole the wrong way around which would then mean removing the box and turning it around to "drop" the wrongly assembled bits out... That wouldn't be nice!



yep, made sure the lever travel and angle of rotation is identical to the stbrd one. Have a feeling it wasn't so before with problematic engine lever on astern moving a few degrees less than the other engine (obviously moving the other way) but will try again and establish at which travel angle oil starts moving towards the plates. Don't know how progressive is that.tbh

thank you both for the interesting pointers will hopefully test some/all of them and report again

cheers

V.

Have you considered that could have been deliberate by p/o to offset a problem engaging forward on that engine??? Just a thought

 

[vas]

Re: port gearbox works only on reverse

Have you considered that could have been deliberate by p/o to offset a problem engaging forward on that engine??? Just a thought

yes, but it looks like it's the actual construction of this holding plate with the three arrows where the lever sort of stops and holds in place (difficult to explain) but yes, no it's not that.

Quick (unsuccessful) update, popped down to check the lines as wind is picking up and had a go at swapping the diverter axle from port to stbrd. Unfortunately, they look identical, the valve is the same (needs some effort to blow through it on either side) and still port box does bugger all in astern and works fine in reverse with the stbrd side diverter axle.
Similarly stbrd box with the port diverter axle works fine on both astern and reverse...

Also added the WIKA gauge on the stbrd box, started up the engine, let it idle for a few mins, pressure still zero, engaged both astern and reverse for up to 30secs no pressure recording, axle was working fine, boat trying to move.
So definitely some issue to address regarding the pickup point.

Had a look at the plugs mentioned in the manual, they are round with a smallish hole in the middle, doesn't look like hallen or torx. Will have to try again on that.
Also need to wire a dial to the original gauges and see if they work, although logic fails in this respect!

ideas welcomed as always!

cheers

V.

 

[petem]

Re: port gearbox works only on reverse

Anyone remember the £1000 Boxster on Wheeler Dealers? What was believed to be a knackered auto gearbox was fixed with an oil change.

 

[vas]

Re: port gearbox works only on reverse

Anyone remember the £1000 Boxster on Wheeler Dealers? What was believed to be a knackered auto gearbox was fixed with an oil change.

nice one Pete,

I try avoid believing in miracles, but it's on the plans to change the oil.
will probably dismantle the pump for checking the diverter body/assembly

cheers

V.

 

[burgundyben]

Re: port gearbox works only on reverse

Vas

You ran this transmission on ATF when it should be mineral oil? Correct?

Exactly what was the spec of the ATF?

 

[superheat6k]

Re: port gearbox works only on reverse

What grade of auto transmission fluid have you used ?

Twin Disc recommended simple SAE30, but I would expect 15W40 multigrade would be OK, but I wouldn't use a gear oil with EP (extreme pressure) or Hypoid characteristics, and definitely not molybdenum suphide (molyslip). For the clutches to engage they have to displace the oil to achieve drive, so extreme pressure or super slippery additives might not work, although I would expect this to affect both clutches ahead and astern.

The oil change suggested may be worth a try, and got to be simpler than removing the gearbox..

 

[rafiki_]

Re: port gearbox works only on reverse

Vas, am I right in recalling that the box worked ok when you first relaunched MiToS? Sorry to be a pedant, but has anything changed since you launched? You are running on the original gearbox oil? Unless the oil has that nasty burnt smell, it is unlikely to have degraded so much to cause a failure? It just feels to me that one of the ports or valves is blocked. The challenge is to find which one. Changing the oil might work if this displaces the guilty particle.

 

[vas]

Re: port gearbox works only on reverse

Vas

You ran this transmission on ATF when it should be mineral oil? Correct?

Exactly what was the spec of the ATF?

Ben, NOT correct, I simply haven't changed the oil. Apologies, was just WONDERING what's the impact of using the wrong oil...
Actually from today's removal and swapping of the diverter axle, the oil that came out with them was nice and clean thin oil, NOT the red or blueish ATF, so feels like the oil is not the culprit.

The oil change suggested may be worth a try, and got to be simpler than removing the gearbox..

very true spotted the emptying plug today, easy to undo and enough space to slip a tray to pickup the oil.

Vas, am I right in recalling that the box worked ok when you first relaunched MiToS? Sorry to be a pedant, but has anything changed since you launched? You are running on the original gearbox oil? Unless the oil has that nasty burnt smell, it is unlikely to have degraded so much to cause a failure? It just feels to me that one of the ports or valves is blocked. The challenge is to find which one. Changing the oil might work if this displaces the guilty particle.

Correct Paul,

worked fine for the first 100nm after the refit. No nasty smells, oil looks nice and smooth and the right motoroil light colour.
Nothing changed at all.
Blocked valve/port/something makes sense, SOME of them can be checked removed on the spot. So may have to go ahead as other than testing with a VDO dial and/or finding another place to tap and get pressure I don't think I'm getting anywhere tbh.

cheers

V.

 

[rafiki_]

Re: port gearbox works only on reverse

Yes, a real pita after all you have achieved over the years. Sounds like a few evenings reading the manual or parts breakdown to try to understand which ports to check. Good luck.

 

[superheat6k]

Re: port gearbox works only on reverse

I have just read through the manual, and in particular the fault finding chapter, which doesn't mention the issue you have as a possibility.

But it does specifically mention that Low or No oil pressure are key here.

Have you the oil pressure check point mentioned here, if so have you tried your gauge here ...

 

[petem]

Re: port gearbox works only on reverse

nice one Pete,

I try avoid believing in miracles, but it's on the plans to change the oil.
will probably dismantle the pump for checking the diverter body/assembly

cheers

V.

The Wheeler Dealer vid is on YouTube. Worth a watch for entertainment if nothing else.

By the way I'm still waiting for you to send me the diameter of your fenders so that I can send you some sock material.

Cheers, Pete

 

[KevB]

Re: port gearbox works only on reverse

A long shot but I've seen the term "trolling valve" mentioned on the web with these type of gearboxes... you haven't one that has inadvertently been turned on?

http://www.thehulltruth.com/boating-forum/82416-diesel-trolling-valve.html

 

[kashurst]

Re: port gearbox works only on reverse

Hi Vas, been following the thread and I have been looking at other related sites
found this http://www.canalworld.net/forums/index.php?showtopic=47008
the gearbox in bits is smaller than yours but they all work in a similar fashion and it shows the jist of what to expect inside (until you get really big). I think yours will split in the direction of the axles rather than top to bottom to make sure the shafts stay perfectly parallel.
In the event that changing the oil doesnt do the trick getting the box apart isn't difficult. Fingers crossed anyway

 

[vas]

Re: port gearbox works only on reverse

I have just read through the manual, and in particular the fault finding chapter, which doesn't mention the issue you have as a possibility.

But it does specifically mention that Low or No oil pressure are key here.

Have you the oil pressure check point mentioned here, if so have you tried your gauge here ...

I do have some similar access points but they are in awkward spots that force you to remove one of the M10 screws holding the diverter assembly in place in order to tap into them. So, yes, got the points, haven't tried them.
Got an update after the replies, so bear with me.

The Wheeler Dealer vid is on YouTube. Worth a watch for entertainment if nothing else.

By the way I'm still waiting for you to send me the diameter of your fenders so that I can send you some sock material.

Cheers, Pete

entertainment value rather high, time wasted way too much (saw three of the vids!) I''ll have to decide what I'm going to do with my fenders before telling you what size they are as the ones I currently use are in rather bad condition so looks like I'll buy 4 or 6 polyform (is that right brand) medium sized ones locally and once I do that I'll ask you... Further I also owe you a few pics with the letters you helped me design, remember? Still haven't had the time to glue them on!!!

A long shot but I've seen the term "trolling valve" mentioned on the web with these type of gearboxes... you haven't one that has inadvertently been turned on?

no trolling valves installed I'm afraid

Hi Vas, been following the thread and I have been looking at other related sites
found this http://www.canalworld.net/forums/index.php?showtopic=47008
the gearbox in bits is smaller than yours but they all work in a similar fashion and it shows the jist of what to expect inside (until you get really big). I think yours will split in the direction of the axles rather than top to bottom to make sure the shafts stay perfectly parallel.
In the event that changing the oil doesnt do the trick getting the box apart isn't difficult. Fingers crossed anyway

Thanks, I do have the service manual, it's not difficult to take it apart, not sure about "shimming" and putting it back together. Box is around 50kg, so not impossible to remove, but I want to eliminate all the easier options first

So, update:

Removed oil from offending box:
Amount of oil removed looks right (should as dipstick was ok)
Colour and texture look right, but worked (as it is) Cannot say if oil is 15yo (as in original!) or not, as ppl here argue that there's no point in changing box oil, only topping up :ambivalence:
Plug came nice and clean, no debris on the hollow section, nothing at all, I like that point!

Plugged it again and filled with new SAE30 oil. Got it about right on the dipstick, started up engine, astern fine (as was before) ahead, bollx (as was before). Played with the lever a bit, sometimes when I was turning hard from neutral to ahead, it would start slowly turning, some others not. Not a conclusive result, but when I was turning the lever and pushing it further than it's normal groved spot for ahead, axle would move v.slowly, if I'd casually turn the lever to ahead without forcing it, it would do bugger all.

So, next step was to remove the pump out of the offending box. Had to, as diverter is UNDER the pump. 4 M8 bolts and a bit of tapping and off it came. Looked nice and clean inside and considering that astern worked fine, there's no way in hell that it's the pump to blame.

Just to be 100% sure, I removed the stbrd pump, and fitted the port one in it's place. All worked fine on stbrd box. So established that indeed pump of the port box is fine.

Next step was to remove the diverter assembly. A few more allen and hex M10 bolts a bit of tapping and off it came (heavy thing!)

Also looks nice and clean but needs careful checking on better lighting conditions and after some thorough cleaning.

Was running out of time so didn't do the final test I wanted to:
remove the stbrd diverter assembly and fit it on port box and try it!

Since it's unlikely I'll be able to spend some time during the first part of the week, I decided to take the diverter to my machinist and blow it clean with petrol and compressed air and then try to blow air through the pump outlet and see if the diverter lever actually works.
Assuming the twindisk MG502 is not inverted to the TM170/880, the axle that does the port box fwrd movement is the one that the pump is mounted. It's the longest route for the oil that starts from there, goes to the cooler comes back to the diverter assembly on the wrong side of it (on top of the reverse axle) and then goes to the diverter and to the axle. Anyway, a bit of blowing will show if the thing works or not.


and a few pics of the box sans diverter assembly:

and the black sort of deposits on the two faceplaces of the diverter assembly, no debris, just black soot (if you can call it that):

Hopefully tomorrow I'll have a first idea if oil (and air!) moves about where it should.

any ideas as always welcomed!

cheers

V.

 

[vas]

Re: port gearbox works only on reverse

hm,

maybe found the problem.

checking under decent light the assembly with the machinist, the end bearing where the main axle turns and where the pump bolts on, is unevenly worn. Means pressure can easily escape back and not press the disks (says me...)

anyway, Vangelis kept the assembly to test pressure clean and establish that the diverter works fine, but looks like he'll either have a go at making another sleeve for it, or I have to buy this part.

I wonder if stbrd is letting go as well
I also wonder how this happens, as axles turn on decently sized bearings on both ends of the casing, it's a matter of protruding around 40mm for the oil pressure transfer to work....

Since boat is still on the water, I'm reluctant to remove the other diverter assembly as yet, so will see what Vangelis thinks of this first. Got to carefully measure the axle for the sleeve (if he decides to do that), mind axle didn't look or feel worn, but have to try again with more light.

Anyone hazard a guess of the cost of this part, or who may keep them in stock?

cheers

V.

 

[vas]

Re: port gearbox works only on reverse

and a final post for me before getting back to "real" work, to note that on the service manual they show two seal rings on the narrower first and third groove of the axle, second groove is where the oil hole lives, which were not there on disassembly.
Totally dissintegrated in 600h?
Missing or changed from the manual setup and stopped using them?
I also wonder how a (silicone I presume) seal ring can withstand the temps and constant wearing on the turning axle.
Tempted to get two silicone seals and try it on tbh.

Items 11 on top assembly and 34 on lower:

cheers

V.

 

[petem]

Re: port gearbox works only on reverse

entertainment value rather high, time wasted way too much (saw three of the vids!) I''ll have to decide what I'm going to do with my fenders before telling you what size they are as the ones I currently use are in rather bad condition so looks like I'll buy 4 or 6 polyform (is that right brand) medium sized ones locally and once I do that I'll ask you... Further I also owe you a few pics with the letters you helped me design, remember? Still haven't had the time to glue them on!!!

You're talking to an expert here on wasting time watching Wheeler Dealers. Of the 100 made, there's probably about 10 stand out ones if you want to be more selective!

Cool, let me know about the socks, no rush.

Regarding the letters, get some narrow 3m VHB tape (eBay) and get the wife or kids to cut it into pieces and stick it on. Note that the tape comes in various thicknesses that you might be able to use if you have a slight curve where you're fitting the letters. Pics would be great!

 

[rafiki_]

Re: port gearbox works only on reverse

and a final post for me before getting back to "real" work, to note that on the service manual they show two seal rings on the narrower first and third groove of the axle, second groove is where the oil hole lives, which were not there on disassembly.
Totally dissintegrated in 600h?
Missing or changed from the manual setup and stopped using them?
I also wonder how a (silicone I presume) seal ring can withstand the temps and constant wearing on the turning axle.
Tempted to get two silicone seals and try it on tbh.

Items 11 on top assembly and 34 on lower:

cheers

V.

Vas, hopefully you have found the culprit, and it passes the test of reasonableness as well, as to why it was OK when first re-launched, and then suddenly failed. I guess the seals may have deteriorated after several years being idle, and you have found some of them in the debris.