Technodrive TMC40M clutch slipping?

[PaulGS]

My Beta 722 20hp has under a thousand hours and a regular service record (fwiw!) and was installed with a Technodrive TMC40M gearbox.
I've witnessed a flawless 40 hours of use since I purchased until a day or two ago when the knots through the water seemed a little sluggish for the engine rev. noise (I don't have a meter so don't have high confidence in this). As I returned to my mooring though the engine noise surged without me touching the throttle.
There's good advice elsewhere about adjusting the clutch plate offset by allen key. Unfortunately my unit's lever is on a threaded shaft with a nut. Turning that nut would have the same effect I imagine but I thought I'd seek some advice before possibly making the situation worse rather than better.

 

[BabaYaga]

Not familiar with the problem you are trying to solve, but I have the same engine and gearbox.
My understanding is that the nyloc nut on the threaded shaft is just there to prevent the lever working loose.
The position of the lever on the shaft can be altered by unwinding the clamping bolt on the opposite side and re-tightening.
Edit: Opposite side with regard to the lever.

 

[PaulGS]

Thanks Baba, I don't think that it's a lever position issue. Further internet searching (Facebook beta owners group) suggests that the shaft (upon which the nyloc nut sits) has a hex concavity for adjustment. When I examined the gearbox earlier I saw no such feature; but then, there was a lot of red paint thrown about so it may be present but hidden.

 

[oldmanofthehills]

My Techno drive clutch failed after 2 years. Not covered by warranty. The product is sh*t

it took 5 or more goes to get it to engage forward. We finally beat the oncoming weather by getting it into gear in Camaret in Brittany and motoring for 30 hours without dairing to increase speed beyond 4kts or let the wind drive us instead and save the droning

 

[Bobc]

Try changing the gearbix oil. I had a similar issue with only 300hrs, and changing the oil solved it.

 

[Bobc]

Also, make sure that lever on the gearbox goes ALL THE WAY into gear, with no tension on it.

 

[Boater Sam]

I would suggest ensuring that engagement is fully occuring when you select. Though these boxes are not good, incorrect cable adjustment on such a recent one is the most likely cause.
I fail to see what fresh oil would do.

 

[oldmanofthehills]

Lever fully home, cable correctly adjusted, automatic gearbox fluid in box at right level. Changed gearbox fluid and I could see brown sludge in old fluid- otherwise know as clutchplate friction material. New fluid made no difference and still took up to six goes to get it to engage, and sometimes even then would not. Rather frightening in marinas, downright scary running for shelter under engine with a storm coming in.

The old sintered iron cone clutches on previous two boats never had this problem even after many years and when a 40 year old clutch did slip it was simplicity to fix - I just reveresed the cone so it mildly slpped when going astern.

TC40 failure has cost me £600 for replacement gearbox and today told fitting was £800. So that £1400 on top of the £6000 engine replacement cost 2 years ago and it might happen again.

I will never buy an engine with a Twindisk gearbox again, and I am going to make it very clear to Beta Marine, that their combined packed is rubbish as their bought in part is not fit for purpose

 

[Tranona]

Lever fully home, cable correctly adjusted, automatic gearbox fluid in box at right level. Changed gearbox fluid and I could see brown sludge in old fluid- otherwise know as clutchplate friction material. New fluid made no difference and still took up to six goes to get it to engage, and sometimes even then would not. Rather frightening in marinas, downright scary running for shelter under engine with a storm coming in.

The old sintered iron cone clutches on previous two boats never had this problem even after many years and when a 40 year old clutch did slip it was simplicity to fix - I just reveresed the cone so it mildly slpped when going astern.

TC40 failure has cost me £600 for replacement gearbox and today told fitting was £800. So that £1400 on top of the £6000 engine replacement cost 2 years ago and it might happen again.

I will never buy an engine with a Twindisk gearbox again, and I am going to make it very clear to Beta Marine, that their combined packed is rubbish as their bought in part is not fit for purpose

Replace it with a PRM90. Minor adjustment to mounts required as slightly longer and centre of output lower, and box is a bit more expensive, but well worth it. I changed the spec on mine at the last minute when I worked out that the TMC40 and 2.64:1 reduction is near its limit with a Beta 30. Pleased I did.

 

[Bobc]

I would suggest ensuring that engagement is fully occuring when you select. Though these boxes are not good, incorrect cable adjustment on such a recent one is the most likely cause.
I fail to see what fresh oil would do.

I think the dirty oil in mine was stopping the cone from running cleanly. It certainly made a difference.

 

[iamtjc]

I had an issue once where the cable had become unseated at the morse controller. Probably from chucking fenders in the locker without enough care and a missing retaining clip. It effectively changed the throw of the lever. May be worth a quick check.

 

[doug748]

I think the dirty oil in mine was stopping the cone from running cleanly. It certainly made a difference.

I followed this gearbox travails fairly closely, I suspect you are on the right lines. Beta used to specify 3 year intervals for an oil change, now 1 year

I am thinking the issue is almost certainly not in strength, engineering, basic design or wear - but in the cones becoming prematurely glazed or contaminated. Cloudy oil left overlong or poor adjustment of gearbox cables are prime suspects, though I know of one case were a small amount of swarf was milled in the gearbox and became sintered onto the friction surfaces.

.

 

[bluerm166]

Several references through the thread to ' gearbox oil'.
I see that Beta do this too but I assume and hope this is a loose reference to ATF of the specified grade !

 

[B27]

Are all these problems sailing boats with fixed propellors by any chance?

 

[Bobc]

Are all these problems sailing boats with fixed propellors by any chance?

No

 

[fishermantwo]

Download the Twin Disc manual for the TMC manual and it has a diagram showing the allen key adjustment on the end of that bolt. Take note of what lubricant the manufacturer specifies[Twin Disc]. It is an ATF Dexron 2 or the catapillar spec oil. Dexron 3 and above is too slippery and will cause grief. The correct grade is an SAE 10 hydraulic oil like floor jacks use. Dexron 2 is unavailable in Australia; the closest spec I can find to the manufacturer's recommendation is ISO 32 hydraulic oil. Changing to the right grade ATF might be all that's required.

 

[Bilgediver]

My Beta 722 20hp has under a thousand hours and a regular service record (fwiw!) and was installed with a Technodrive TMC40M gearbox.
Have you checked that the teleflex cable is correctly adjusted and throwing g the gearbox lever the full amount required?
Disconnect the teleflex connection at the gearbox and see if the lever can be moved further with te.eflex disconnected.

What oil is in the gearbox?

 

[doug748]

Download the Twin Disc manual for the TMC manual and it has a diagram showing the allen key adjustment on the end of that bolt. Take note of what lubricant the manufacturer specifies[Twin Disc]. It is an ATF Dexron 2 or the catapillar spec oil. Dexron 3 and above is too slippery and will cause grief. The correct grade is an SAE 10 hydraulic oil like floor jacks use. Dexron 2 is unavailable in Australia; the closest spec I can find to the manufacturer's recommendation is ISO 32 hydraulic oil. Changing to the right grade ATF might be all that's required.

Interesting.

I can't find any reference to the grade of ATF in the Operating Manual that came with mine.

I have a Service Manual for what I assume is the earlier marine unit (TMC 40) and that specifies SAE 20 -W40. The Service Manual for the TMC 40M (my gearbox) just says ATF. I have looked on line at the manual, shown at present on the Beta website, for the TMC 40P and that also says - ATF.

I am not sure what the differences are between the 40 the 40M and the 40P series gearboxes. Anyone know?

.

 

[doug748]

PS

Someone posted this in 2006:

"To follow everyone else - I got the following from Technodrive:

Subject: R: TMC 40 M ATF oil
Date sent: Wed, 22 Sep 2004 10:25:44 +0200
From: "After market" <colletti.mattia@technodrive.it>

you can use any type of ATF oil for the mechanical gearbox TMC 40 M.
Regards,


Alessandro Biondi
Service & Aftermarket
TWIN DISC TECHNODRIVE s.r.l.
via S. Cristoforo, 131
40010 S. M. Decima - BO - Italy"

 

[Bobc]

I think the most important thing with these boxes is to change the oil every year, and make sure it stays clean.