TWIN DISC TECHNODRIVE TMC 40M GEARBOX PROBLEM

[noswellplease]

The TMC40m gearbox came with my new beata 25hp engine some 18 months ago and for some strange reason the gearbox is now faulty and difficult to find the forward gear, reverse is no problem. The original installer is somewhat mystified as only 100 hours on engine. I always felt the unit made excessive noise when above 2,000 revs and the boat seemed reluctant to improve on 5kts. It seems that the drive shaft is now slipping as the mechanic could stop it rotating by just grasping it with his hand so perhaps this has been a problem all along and has been getting steadily worse. Anyway just wondering if anyone else had any similar problems with TMC40M gearbox and what the outcome was? thanks Russ

 

[earlybird]

I suggest that the prime suspect is the adjustment of the gear selector cable, does it push the selector lever on the box fully into the forward position? This might also explain the noise that you have been hearing as the friction drive intermittently took up and released the load. If this has been the situation for 100 hrs, then the forward drive clutch could now have significant wear. I would drain the oil into a clean container to see if it shows any sign of metallic residue, although absence of this does not rule out wear.

 

[PuffTheMagicDragon]

I second the adjustment lever. I would try disconnecting the cables and operating the lever manually to see if the problem persists. Chances are that you will find that the end of the cable needs a slight adjustment to bring it in line with the hole in the lever.
Unless the double-cone has been worn through slipping, there is not much that can go wrong with this gearbox; it is very well made and reliable. (I have two of them fitted on Lombardini engines: my choice over the alternative Hurth)

 

[RivalRedwing]

The manufacturer in Italy will respond to e-mails (in English)

 

[PuffTheMagicDragon]

Technodrive TMC 40 diagrams CLICK HERE

 

[noswellplease]

Many thanks for the suggestions. Unfortunately I changed the gear oil about a month ago so that rules out the oil analysis. The installer checked with the cable disconnected and just operated the lever by hand and formed the opinion that the gearbox is faulty. I would not be qualified to say if the origional set-up was 100 % but I think I'm looking at replacement now as I think I have been lucky to have not been in serious trouble up to this as a consequence of this problem developing. As always advice from other forumites much appreciated. Thanks.

 

[capsco]

If it is only 18 months old I would be looking for, at least, a contribution from the supplier, that is assuming it was installed correctly.

 

[PuffTheMagicDragon]

Before lashing out on a new gearbox I would have it disassembled to see which parts have been damaged. You might well find that it is only the double cone or the fork that actuates it is all that needs to be replaced.

I don't know who your installer is but these gearboxes are simple mechanisms with little to go wrong. The fact that the box is now faulty does not necessarily mean that the original installation was or was not correct.

 

[noswellplease]

I think I will be looking for more than a contribution from the supplier to put things right, I'm thinking new replacement not reconditioned unit should be in order. I'm hoping the source I bought the unit from will take care of things for me and I don't have any hassle. And anyway he also buys much larger more expensive engines than mine from them so I hope an amicable solution can be found.

 

[dutyhog]

Did you ever discover what had been wrong? I have a similar problem, and all suggestions so far haven't fixed it. Gordon

 

[demengel]

I have a TMC40M gearbox & 28HP Beta engine fitted to my Elizabethan 31.
It had recently developed exactly the symptoms you describe. I have taken it up with Beta Marine and am awaiting a reply. I would be interested lo learn how you get on.

Dee

 

[pencema]

It's disheartening to see no new posts to this thread since 2011. Does that mean I'm the only one currently with this same problem? Hard to believe. Anyway, searching elsewhere, I came across what I believe is the actual solution. Loosen the lock nut on the shaft where the shift lever mounts to the transmission. Adjust the clearance for the clutches by turning the "adjusting rod" one quarter turn. This was from a five-year-old Beta Marine forum thread. I'm waiting for warm weather to give it a try.
I previously exhausted all external adjustment routes, and proved to myself that it's not the shift cable causing the problem. It behaves the same with the cable disconnected, and shifting by hand.

MAP

 

[TetjeWind]

Hi,
I also have problems with the technocdrive clutch (TMC40). My engine is brandnew. But when the engine is cold (my installer used the correct atm-oil), it slips during the first turns as you can see in the video. The dealer in germany says, he never had such a case.
I'm astonished, that this seems not be as rarely, as the dealer told me.

 

[pencema]

Your video showed exactly what happened to mine last fall, before it failed to spin at all. I believe the clutch slips, building up heat from the friction. Then as the parts expand, the clutch finally engages. But in the process, it's destroying itself.
In the end, I replaced the transmission, and the new one seems to work fine, although I've only had the boat out once since the replacement.
When I drained the old transmission, there was a lot of metallic residue in the oil. I assume that was from the clutch slipping.

 

[TetjeWind]

Hello pencema,
in my case the transmission and the engine (Vetus M2.13) is new. I bought it in february 2015 an the the engine ran only 2 or 3 hours at all. My installer confirmed that all is fitted correct and I could not imagine what we could have made wrong. Vetus suggests, that I could by a new transmission (1000€) and they would send the "old" one to the producer (Italy) to analyze it. If I'm very angry about it! And at the same time I'm astonished that a new article could fail.
Best regards

 

[Ruben]

Hello pencema,
in my case the transmission and the engine (Vetus M2.13) is new. I bought it in february 2015 an the the engine ran only 2 or 3 hours at all. My installer confirmed that all is fitted correct and I could not imagine what we could have made wrong. Vetus suggests, that I could by a new transmission (1000€) and they would send the "old" one to the producer (Italy) to analyze it. If I'm very angry about it! And at the same time I'm astonished that a new article could fail.
Best regards

 

[Ruben]

Hi, my technodrive suffered same problems. Not grapping when cold. After a while it responds corectly. In my case the shiftbox had some water inside. But has been flushed (with ATF) several times. Still same problem. Are there any other lubricants to flush?

Kind regards,
Ruben

 

[Amlov]

Hi
Yes, I had the same problem on a 10y Beta 20hp with 640h on it. Slow to engage forward but no problems with reverse. I reluctantly replaced the gearbox and out of interest stripped it down. Sure enough the forward clutch cone had no significant wear but was highly glazed. You almost felt that a quick rub with a piece of wet and dry would have solved it. Interestingly, the oil (ATF) which I changed each year always came out a dark colour which suggested to me that it had been overheating.

On the new box I have switched to DEX III as it is more heat tolerant, changed the oil at every 25h (well it is only 200mL) and have been careful not to let the engine run under light load if motor sailing, but still the oil comes out a dark colour.

I don't really have a good idea what causes the problem, but the dark ATF and glazing would suggest overheating and slippage.

Best of luck sorting out your gearbox, but my experience is that the only real solution is a replacement.

Regards

Andrew

 

[Ammonite]

Hi
Yes, I had the same problem on a 10y Beta 20hp with 640h on it. Slow to engage forward but no problems with reverse. I reluctantly replaced the gearbox and out of interest stripped it down. Sure enough the forward clutch cone had no significant wear but was highly glazed. You almost felt that a quick rub with a piece of wet and dry would have solved it. Interestingly, the oil (ATF) which I changed each year always came out a dark colour which suggested to me that it had been overheating.

On the new box I have switched to DEX III as it is more heat tolerant, changed the oil at every 25h (well it is only 200mL) and have been careful not to let the engine run under light load if motor sailing, but still the oil comes out a dark colour.

I don't really have a good idea what causes the problem, but the dark ATF and glazing would suggest overheating and slippage.

Best of luck sorting out your gearbox, but my experience is that the only real solution is a replacement.

Regards

Andrew

You may have already checked this but do make sure the throttle cable isn't being operated before the gearbox is fully in gear. ie. that your teleflex or equivalent is properly adjusted. If the throttle moves too soon this will cause the clutch to slip and the oil turns brown / black

 

[bmreaves]

I have the same problem and I am told the best solution is to replace the gearbox. Based on what I see, it seem to be a manufacturer defect, but manifest itself later. My gearbox started having problems after 400 hours of use.